Plant reproduction, Plant growth.

School Science Lessons
UNBiology1a
2024-01-03
Please send comments to: J.Elfick@uq.edu.au
(UNBiology1a.html)

Flowering plant reproduction, flowers, pollen, seeds, fruit, dispersal
Table of contents
See: Botany, (Commercial)
9.1.0 Flowers
9.2.0 Pollen
9.3.0 Fertilization
9.5.0 Seeds
9.6.0 Fruit
9.7.0 Different flowers

9.1.0 Flowers
9.1.1 Parts of a flower
9.1.2 Flower parts, dicotyledons, K, C, A, G, P
9.1.3 Types of inflorescence
9.1.4 Monoecious, dioecious and hermaphrodite plants
9.1.5 Flower maturity
9.1.6 Flower and fruit formation of tomato

9.2.0 Pollen
9.2.1 Pollen
9.2.2 Pollen from stamens, lily
9.2.3 Pollen grain and male prothallus
9.2.4 Pollen germination

9.3.0 Fertilization
9.3.1 Carpels and ovules, lily
9.3.2 Development of plant embryos
9.3.3 Fertilization, lily
9.6.6 Fate of flower parts, floral organs, (Table)
9.6.7 Post-fertilization changes outside the ovule (Table)
9.6.8 Post-fertilization developments outside the embryo sac
9.6.9 Post-fertilization fate of the endosperm
9.6.11 Zygote development
9.6.12 Zygote development, shepherd's purse

9.5.0 Seeds
See: Seeds (Commercial)
9.5.1 Castor bean, Ricinus communis
9.5.2 Exalbuminous seed, broad bean, Vicia faba
9.5.3 Seed survival after ingestion

9.6.0 Fruit
A fruit is a swollen ovary with one or more seeds inside
9.6.1 Apple, pome
9.6.2 Dry dehiscent fruits
9.6.3 Dry indehiscent fruits
9.6.4 Dispersal of seeds and fruits
9.6.5 Fruit types (Table)
9.6.10 Succulent fruits, "true" succulent fruits, fleshy fruits

9.7.0 Different flowers
9.7.1 Buttercup flower
9.7.2 Chilli flower
9.7.3 Cherry flower
9.7.4 Poinciana flower
9.7.5 Hazel flower
9.7.6 Hibiscus flower
9.7.7 Lily flower
9.7.8 Sweet potato flower
9.7.9 Willow flower

9.1.1 Parts of a flower
See diagram 9.98.7: Parts of a flower.
See diagram 9.98: VS Dicotyledon flower.
Experiment
Hold the flower by the stalk and touch the following parts:
1. Receptacle: Where the stalk gets wider at the base of the flower.
It is a platform for the other flower parts.
2. Sepals: Like little green leaves on the outside of the flower.
They project the young flower in a flower bud.
3. Petals: Coloured parts inside the sepals.
They attract insects.
4. Stamens: The male parts.
Each stamen consists of a little stick called the filament that holds up a bag called the anther.
The anthers produce pollen.
Can you see the pollen coming out of the anthers?
5. Stigma: The top of the female part in the middle of the flower.
It is sticky and can catch the pollen.
6. Style: The long tube of the female part below the stigma.
Pollen can grow down inside the tube to fertilize the ovary.
7. Ovary: The swollen base of the female part that contains ovules.
After fertilization, the ovary will form a fruit and the ovules will form seeds.
Count the number of sepals, petals and stamens.
Then they should pull off some sepals and petals, and open the ovary to see the ovules.

9.1.2 Flower parts, dicotyledons, K, C, A, G, P
See diagram 9.98: Parts of a dicotyledon flower
See diagram 9.98.7: Flowers, floral formula
See diagram 9.4.2: Tomato flower and fruit
See diagram 54.9.2: Chilli flower
A flower grows from the axil of scale leaf or bract and represents a modified shoot.
The flower stalk, pedicel, forms a receptacle as a base for the flower parts arranged in concentric whorls or in spirals.
Flowers may be hermaphrodite with both stamens and carpels or have only stamens or only carpels.
The perianth (P) is usually in two whorls, but may be absent.
The outer whorl of the perianth, the calyx (K), contains the leaf-like sepals that protect the bud.
The inner whorl of the perianth, the corolla (C), contains the petals that are usually showy, coloured and scented to attract insects.
The male part, the androecium (A) refers to the stamens that produce pollen and are arranged inside the corolla.
The female part, the gynoecium (G) or pistil, refers to the carpels in the centre of the flower.
The carpels contain the ovules that form seeds after fertilization.
Fruits develop from the carpels, and sometimes other structures.
The floral formula shows the number of parts in the calyx (K) corolla C) androecium (A) and gynoecium (G).
Perianth (P) is used when no separate calyx and corolla exist.
The symbol "oo" (infinity) stands for a large and indefinite number of parts.
Fusion between parts is shown by brackets round the number, e.g. K(5) = fusion of 5 sepals (K 5 means 5 separate sepals).
Experiments
1. Dissect flowers and write the floral formulas, e.g. hibiscus, tomato, lily, chilli, buttercup, larkspur, marsh marigold, shepherd's purse.
2. Cut the ovary crosswise and count the ovules or "seed pockets".
Look for seeds in the ovules.
3. Rub an anther from a stamen on black paper to see the pollen will usually be seen.
Observe the pollen with a microscope.

9.1.3 Types of inflorescence
See diagram 9.99: Types of inflorescence
Plants can bear flowers singly or grouped in an inflorescence.
Each flower usually has its own stalk, the pedicel.
Where the pedicels join the main stalk, the peduncle, is a bract.
A spadix is a fleshy spike covered with male and female flowers, e.g. arum lily.
Collect plants with different types of inflorescence.
Experiment
Observe the peduncle, pedicels, and bracts, and their relative positions.
1. Each flower usually has its own stalk, the pedicel.
Where the pedicels join the main stalk, the peduncle, is a bract.
2. A spike is a simple axis with successively younger sessile flowers, so it has no pedicels, e.g. Gladiolus, red clover.
3. A catkin is a unisexual spike without petals that usually hangs down, e.g. mulberry, willow, oak, birch
4. A spadix is a fleshy spike covered with male and female flowers, e.g. arum lily.
5. A raceme is similar to a spike, but the flowers have pedicels, e.g. sweet pea.
6. A panicle is an open, repeatedly branched raceme bearing many flowers, e.g. oats and other grasses.
7. A corymb is a raceme with all flowers at one level with the youngest flower in the centre, e.g. apple, rowan, hawthorn.
8. An umbel has flower stalks all arising together at the end of the main stalk, e.g. carrot, parsley, fennel, frangipani, Hydrangea, Lantana.
9. A capitulum (head), has flowers densely packed on a receptacle with the youngest at the centre, e.g. sunflower, dandelion, daisy.
10. A cyme has the main axis ending in a flower, the oldest flower, with younger flowers on lateral branches, e.g. tomato.
11. A spathe is a huge bract that can enclose the inflorescence, e.g. coconut.
Experiments
Collect plants with different types of inflorescence.
Observe the peduncle, pedicels, and bracts, and their relative positions.

9.1.4 Monoecious, dioecious and hermaphrodite plants
Male and female gametes may be on the same flower or on different flowers.
Hermaphrodite, bisexual, perfect flowers have male and female organs.
Complete flowers have male and female organs and petals and sepals.
Monoecious plants have separate male and female flowers on the same plant, e.g. maize Zea mays.
Dioecious plants have separate male and female flowers on separate plants, so they have male plants and female plants, e.g. holly, ginkgo, persimmon

9.1.5 Flower maturity
Collect specimens of flowers of roses, apples and tomatoes, in different stages of maturity, from newly-opened buds to specimens in which the petals have fallen.
Cut each ovary open, and note the changes that take place during seed development.

9.1.6 Flower and fruit formation of tomato
See diagram 9.4.2: Tomato flower and fruit formation
Collect some green tomatoes and tomato flowers, one of each for each group of four students.
You could also use chilli or eggplant (aubergine) fruit and flowers.
You will need some razor blades and a magnifying glass.
Examine the flowers and fruit, cut them down the middle with razor blades.
BE CAREFUL! Show them the ovary (fruit) and ovules (seed).
The remains of the sepals, petals, stamens, stigma, style, may be seen if they have not dropped off.
After pollen sticks to the stigma and grows down the style into the ovary, the ovary swells to form a fruit.
The ovules in the ovary become seeds.
Pollination is when the pollen touches the stigma and sticks to it.
Big flowers are pollinated by insects.
Small flowers such as grass are pollinated by the wind.
Fertilization is when the male pollen reaches the ovary and ovules.
The pollen grows down the style to the ovary.
Tell the students to draw their cut tomato flowers and fruit.
After fertilization, the flower stalk becomes the fruit stalk, the sepals, petals, stamens, stigma and style usually die, the ovary becomes the fruit, the ovules become seed.

9.2.1 Pollen
1. The stamens are attached to the receptacle inside the corolla and outside the carpels.
Each stamen consists of a filament like a little stem and terminal anther that produces pollen.
The anther has of four sporangia, each occupying a lobe.
The sporangia are held together by parenchyma tissue with a small vascular bundle called the connective.
An adnate anther is fused to the filament, Ranunculus.
A versatile anther swings loosely at the end of the filament, lily.
Most anthers open by a longitudinal slit down each side so that the pollen from the two contiguous sporangia is shed simultaneously.
Some anthers shed pollen by terminal pores.
A transverse section of a young anther shows four locules or sporangia, two on each side of the connective with its vascular bundle.
Each sporangium has an epidermal layer of cells with a thin cuticle, a fibrous layer of cells, parenchyma cells, and a tapetum, composed of a single layer of cells with large nuclei and dense contents and.
projecting into the sporangium.
The tapetum nourishes the pollen-mother-cells (spore-mother-cells) inside that have thick walls, dense cytoplasm, and a large nucleus.
As the anther matures, each diploid pollen-mother-cell divides by meiosis to form four haploid pollen grains.
The walls of the pollen-mother-cells breakdown to release the pollen grains.
Dehiscence occurs between the two contiguous sporangia where the cells have thin walls and readily split apart under tension when the cells of the fibrous layer contract.
The split extends down each side of the anther to liberate the dry pollen grains.
Weatherzone Pollen Index
In Brisbane, the Weatherzone Pollen Index measures the potential for pollen to trigger allergic reactions in susceptible people.
Pollen levels in the atmosphere will be highest on hot days and on days where a dry wind is blowing.
Additionally, light rain overnight or during the early morning will also cause high pollen levels.
Pollen allergy
These are the days when you will experience the telltale symptoms of a runny nose, watery eyes, itchy skin and nasal congestion.
Some people are allergic to honey, e.g. dandelion honey, because of the pollen it contains.
Honey may be sold coming from different flowers, e.g. karri, white clover or as a blend.
So blended honey sold in markets may not contain pollen, because they are filtered.
Testing different honey for allergies to them may be too dangerous for school science experiments.
Experiment
Pollen carried by wind can be taken to very high altitudes or hundreds of kilometres, but most pollen is carried small distances.
To test distance, select a plant that sheds lots of pollen with a distinctive shape and where there are no other plants of this species in the area, e.g. a pine tree on a farm, Juncus rush where there are no other rushes.
Expose slides coated with Vaseline for one day or use a pollen sampler containing pre-greased polystyrene rods.
A thin coat of silicone grease captures the pollen and mould spores on the rod.
Apply Calberla's pollen stain to stain the pollen light pink, then count the pollen under a coverslip with a 400 X light microscope.
See 3.5.4: Calberla's pollen stain

9.2.2 Pollen from stamens, lily
See diagram 9.98.2: Lily stamen
Experiment
Cut sections of anthers Place the anthers of a lily flower, or other large anthers, in alcohol for about a week.
Cut transverse sections, mounting in glycerine, and note the structure as described in the text.
Also, buds of marsh marigold also harden alcohol and may be sectioned at the level of the anthers.

9.2.3 Pollen grain and male prothallus, lily
See diagram 9.98.3: Lily pollen grain
Each pollen grain contains a small generative cell and a large tube cell.
Pollen grains shed from the anthers are carried by wind or by insects to a stigma, the receptive part of the gynoecium.
Germination of the pollen is induced by the secretion from the stigma.
The large tube cell divides to form the pollen tube that grows through pores in the wall of the pollen grain then grows down through the style tissue to reach the ovary.
The small generative cell divides to form two male cells that function as gametes and may seem naked nuclei.
As the pollen tube emerges from the pollen grain, the tube nucleus passes to the tip of the pollen tube leaving behind the two male cells.
The pollen tube and its two small cells represent the male prothallus found in more primitive plant forms, liverworts, mosses, ferns and conifers.
The germination of pollen grains can be studied using different concentrations of sugar solutions.
Experiment
Observe the germination of pollen grains.
Put fresh pollen in a 10% sugar solution for 12 hours and examine them with a magnifying glass.
You may find germinating pollen on the stigma of a flower.
Observe pollen stained with methylene blue under low power.
Observe the germination of pollen in the styles of chickweed, taken from a flower that is just beginning to fade.
Mount the styles in a dilute aqueous solution of methylene blue.

9.2.4 Pollen germination
See diagram 9.123: Germinating pollen grain
Experiment
Make a strong sugar solution and put it in a shallow dish like a saucer.
Shake pollen from several kinds of flowers on to the surface of the sugar solution.
Cover with a sheet of glass and let it stand in a warm place for several hours.
Observe little tubes growing from the pollen grains.
Use a magnifying glass.

9.3.1 Carpels and ovules, lily
See diagram 9.98.4: Lily gynoecium
See diagram 9.98.5: Lily ovule
Carpels
The carpels appear in the centre of the flower, and usually end the growth of the floral axis.
Together, the carpels form the gynoecium (pistil).
An apocarpous gynoecium has separate carpels, Ranunculus.
A syncarpous gynoecium has fused carpels. lily 3 fused carpels.
The gynoecium of legumes is a single carpel.
Each carpel consists of three parts:
1. The ovary at the base contains the ovules.
2. The style is an extension of the ovary.
3. The stigma at the end of the style secretes a sticky, sugary fluid to catch the pollen grains.
Ovule
The ovule consists of a mass of cells, the nucellus (megasporangium), surrounded by two rings of tissue, the integuments.
Megaspores
The nucellus develops the diploid megaspore-mother-cell, which divides by meiosis to form four haploid megaspores, while the megaspore-mother-cell becomes a large oval cell called the embryo sac.
Of the four megaspores in a row in the embryo sac, only the megaspore nearest the food supply and farthest from the micropyle survives, because it crushes and absorbs its three sister megaspores.
The surviving megaspore divides by three mitosis divisions to form the eight nuclei of the embryo sac (2 synergids, 1 ovum, 3 antipodals, 2 polar nuclei).
At the micropyle end of the embryo sac are three nuclei or cells surrounded by cytoplasm with thin membranes.
Two of these cells are pear shaped and called the synergids.
Ovum
The third cell is the globular ovum.
At the other end of the embryo sac are three cells called the antipodals.
In the centre of the embryo sac is the large fusion nucleus formed by the fusion of two polar nuclei.
The embryo sac that represents the female prothallus is still surrounded by cells of the nucellus.
Placentation
Placentation refers to how the ovules are attached to the placenta in the ovary.
1. Parietal placentation is where the ovules are attached to the wall of the ovary, poppy.
2. Axile placentation is where the ovules are attached to the central axis of a multilocular ovary, lily.
3. Free central placentation is where the ovules are attached to the axis, but the ovary is unilocular, primula.
The stigma is hollow or contains loose mucilage secreting cells to help the pollen tubes reach the ovarian cavity.
The pollen tube probably absorbs nutrients from this style tissue in flowers with long styles.
Experiment
Cut sections of ovules.
Take a just-opened flower of marsh marigold and remove the sepals and petals.
Harden the group of carpels in alcohol and then cut transverse sections of these.
Cut many sections and pick out a few thin ones which have traversed an ovule and mount in glycerine.
These will give longitudinal sections of the ovules, which can be compared with the figures in the text.
Transverse sections of syncarpous ovaries should also be cut, tulip and lily.

9.3.2 Development of plant embryos
Experiment
Put seeds in a flat dish, add water, and wait for the seeds to swell.
To study embryos in an early stage of development, put the swollen seeds on moist absorbent paper and leave them until the desired stage has been reached.
To study seeds in a later stage of development, put the swollen seeds in a flowerpot filled with damp sawdust or sand.
When the plants have reached the desired stage of growth, remove them from the sawdust or sand and rinse under water.
Open the carpels of embryo plants at different ages, e.g. shepherd's purse.
Remove the ovules and put them in a drop of 5% potassium hydroxide solution on a microscope slide.
Put a coverslip over them and press down on the coverslip with a thumb wrapped in absorbent paper or a scalpel handle to squeeze the embryos out of the ovules.
Be careful not to break the coverslip, because the broken pieces are very sharp.
Check with the microscope after each time you press down on the coverslip.
Examine the preparation to find embryos in different stages of development.

9.3.3 Fertilization, lily
See diagram 9.98.6: Lily fertilization
The end of the pollen tube in the cavity of the ovary, enters the micropyle, penetrates the nucellus tissue, enters the embryo sac and bursts to set free its two male gamete cells.
One male gamete unites with the ovum to form the zygote, the essential act of fertilization.
The other male gamete cell unites with the fusion nucleus to form the primary endosperm nucleus or triple fusion nucleus.
The synergids and antipodals shrivel and die.
In angiosperms, the endosperm develops only after fertilization.
The triple fusion nucleus divides to form thin walled parenchyma tissue that accumulates food reserves, starch, oil and protein.
As the endosperm develops, it crushes the nucellus.

9.5.1 Castor bean, Ricinus communis
Albuminous seed, castor oil plant
See diagram 9.103: Castor seedling
Experiment
Observe the embryo, with its hypocotyl, radicle and plumule.
he cotyledons are thin and tissue-like.
The seed is albuminous.
Observe the testa surrounding the seed.
Test the food reserves present in the seeds.

9.5.2 Exalbuminous seed, broad bean, Vicia faba
See diagram 9.110.1: Broad bean, hypogeal germination
1. Soak the seed for twenty four hours before dissecting.
Experiment
Observe the embryo, with its hypocotyl, radicle and plumule.
The cotyledons are thick and fleshy.
The seed is exalbuminous.
Observe the testa surrounding the seed.
Test the food reserves present in the seeds.
2. Examine the soaked seed.
Observe the hilum, elongated brown scar, at one end of the seed.
At this point the seed was attached by a stalk to the inside of the fruit.
3. Remove the testa, seed coat, to reveal the embryo.
The embryo consists of two large fleshy cotyledons attached to a small axis.
The tips of the axis are the radicle, embryo root, and plumule, embryo shoot.
The radicle can be seen at one side where it was inserted into a pocket in the testa.
Remove one cotyledon to reveal the plumule.
Apply some dilute iodine solution to a broken surface of the cotyledon and note the positive reaction to the starch test.

9.5.3 Seed survival after ingestion
Some seeds eaten by animals survive the passage through the alimentary canal and end up in the animal dung.
Find what proportion of seeds survives the alimentary canal and which seeds are distributed in dung.
Relate seed size and structure with survival in animals with different types of digestive systems.
Select seeds from those normally eaten by animals e.g. oats, clover, medic, rye grass.
Include tomato which has a high percentage of survival through alimentary canals.
Use two animals with a contrasting alimentary canals e.g. hens and rats.
Large animals, e.g. horse, require a lot of sieving of their manure.
Compare live seeds in initial samples before ingestion with seeds material, which have passed through the animal.
Dung of the cassowary from the tropical rainforests of North Queensland showing the undigested seeds of the Alexandra Palm, Archontophoenix alexandrae.
The cassowary has a very gentle and fast moving digestive tract, so some seeds pass through them without being fully digested.

9.6.1 Apple, pome
See diagram 9.100.5: Pome, apple
See diagram: Malus domestica, common apple.
See diagram 9.5.1: Fleshy fruits
Experiment
Cut one apple vertically through the centre, a VS section, and cut another apple horizontally through the middle, a TS section.
Observe the parts as in the diagram.
The apple has a core in the middle of the fruit containing pips, the seed of the apple tree.
So the apple is a pip fruit.
The pear and quince are other examples of pip fruits, but the core is surrounded by the mesocarp or fruit pulp enclosed by the peel.

9.6.2 Dry dehiscent fruits
The fruit of dry dehiscent fruits opens to let the seeds out.
See diagram 9.100.8: Dry dehiscent fruits
See diagram 9.5.2: Fruit types, Dry fruits
Experiment
Collect different fruit, slice each fruit transversely and longitudinally, and determine the type of fruit.
9.6.2.1 Capsule
9.6.2.2 Follicle
9.6.2.3 Legume, pod
9.6.2.4 Lomentum
9.6.2.5 Silique (siliqua)

9.6.3 Dry indehiscent fruits
The fruit of dry indehiscent fruits do not open to let the seeds out
9.6.3.1 Achene
9.6.3.2 Caryopsis, (grain)
9.6.3.2.1 Popcorn, pericarp of maize
9.6.3.3 Cypsela
9.6.3.4 Nut
9.6.3.5 Samara
9.6.3.6 Schizocarp

9.6.4 Dispersal of seeds and fruits
1. Dispersal by animals
Birds eat fleshy parts of blackberry or cherry drupes, but not the hard seeds protected by a hard endocarp.
Birds are irritated by the sticky receptacle of mistletoe fruit, so it wipes the fruit on branches.
Animals carry hooked fruits, burs, in their coats, e.g. capitulum of common burdock covered by spiny bracts.
The weed cobbler's pegs has toothed bristles that attach the fruit to your socks.
2. Dispersal by wind
Dandelion, thistle and other Compositae have a ring of white hairs, pappus, to form a parachute and carry the achene.
Seeds of willow have tufted hairs.
Poppy has a pepper-pot mechanism to shake out tiny seeds from its capsule.
Similarly Eucalyptus and Leptospermum have a capsule that opens by slits.
The fruit of the castor bean, Ricinus communis, suddenly split apart to throw out seeds.
Clematis and wood avens have plumed fruit.
The elm tree and the ash tree have winged fruit.
Orchids have extremely light seeds.
Spinifex and various "tumble weeds" produce a ball-like cluster of fruits to be bowled along by the wind.
3. Dispersal by water
Water lily seeds and fruit can float.
Also, coconut fruits can float, but they may not be viable after some time.
4. Mechanical dispersal
The drying pods of peas, beans, Wistaria and other legumes twist to send out seeds like a catapult.
Geranium has a splitting schizocarp.
The squirting cucumber, Ecballium, squirts out its seeds.
Experiment
Examine the dispersal mechanisms of seeds and fruits.
5. 6.4.13 Dispersal of pine seed by swelling movements

9.6.5 Fruit types
See diagram: Fruit types, Fleshy fruits
See diagram: Fruit types, Dry fruits

Fruit types	Description	Examples
-	Dry Indehiscent Fruits	-
Achene	1 carpel, one seed attached to hard pericarp	buttercup, sunflower
Caryopsis (grain)	fused carpel and seed coat	cereals, grasses, wheat, maize, rice
Samara	pericarp forms wings	maple, sycamore, ash
Cypsela	2 carpels, like achene, but inferior ovary	dandelion, sunflower, daisy
Schizocarp	syncarpous ovary splits when ripe	geranium, mallow, hollyhock
Nut	more than 1 carpel, woody wall	macadamia, hazel, chestnut, walnut, oak nut (acorn)
	Dry Dehiscent Fruits	-
Follicle	1 carpel, dehisce along one margin	oleander, larkspur, grevillea, kurrajong, columbine
Pod Legume	1 carpel, dehisce along both margins	Fabaceae, pea, bean, lentil, acacia, peanut, tamarind, fumewort
Lomentum	1 carpel, pod constricted between seeds	Desmodium, Entada, Hedysarum, Lotus
Silique	1 carpel	pod of Cruciferae, shepherd's purse, stock, cabbage
Capsule	3+ carpels, dehisce by pores or splits	Eucalyptus, tea tree, poppy, lily, pansy, violet, iris, snapdragon
-	True Succulent Fruits, Fleshy Fruits
Berry	2+ carpels, pericarp = skin epicarp, fleshy or fibrous mesocarp, thin skin endocarp (pepo or gourd has one cavity, pulp interior)	chillies, tomato, capsicum, eggplant, banana, gooseberry, date, currant, grape, avocado, papaya, passion fruit, allspice (pimento), pomegranate, guava, mangosteen, carambola (star fruit) (pepo: pumpkin, melon, cucumber, marrow, squash, snake gourd)
Drupe	1 superior carpel, pericarp = skin epicarp, fleshy or fibrous mesocarp, thin skin endocarp stony endocarp encloses seed (kernel)	apricot ("stone fruit"), almond, cashew, cherry, cocoa, coconut, coffee, mango, nutmeg, peach, pepper, plum (walnut has 2 carpels, so a walnut is not a "nut")
"False" fruit	False Succulent Fruits, Fleshy Fruit	-
Pome	"core" = ovary, fleshy receptacle	apple, pear, quince
Hesperidium	many fused carpels, with pulp and tough rind containing oil glands	grapefruit, lemon, lime, orange (citrus fruit)
Aggregate fruit, syncarp	collection of several carpels from one flower	pineapple, custard apple, rose hip (achenes) strawberry (achenes) blackberry, breadfruit, jack fruit, fig (syconium) raspberry, blackberry, mulberry, pandanas

9.6.6 Fate of flower parts, floral organs
Table 9.3.18.0

Ovule	Seed
Integuments	Seed coats
Nucellus	Shrivels to thin papery layer
Fusion nucleus of the embryo sac	Endosperm tissue for food storage and nutrition of the embryo.
Ovum	Embryonic plant
Antipodals.	Usually shrivel, sometimes persists as absorbing mechanism for endosperm
Synergids	Usually shrivel and are absorbed by the developing embryo

9.6.7 Post-fertilization changes outside the ovule
Table 9.3.17.0

Hermaphrodite flowers.	Stamens and pistil in the same flower, Most familiar flowers, legumes, rose, potato, Grevillea, Primula
Monoecious (unisexual) (diclinous)	Stamens and pistil in separate flowers on the same plant, beech, oaks, hazel, sycamore
Dioecious (unisexual).	Stamens and pistil in separate flowers on different plants, date palm, willow, poplar, hop

9.6.8 Post-fertilization developments outside the embryo sac
In most angiosperms, the nucellus is exhausted by the development of the ovule.
In ripe seeds, it may be present as a thin membrane between the endosperm and the seed coats.
The integuments of the ovule form the permanent seed coats that are thin and membranous in some species hard and woody in others.
When the funicle attaching the seed to the placenta dies, the seed is separated from the ovule and is ready for dispersal.
When the seed is shed from the plant, it may not germinate, because it requires a period of dormancy.
The ovule becomes a seed.
The ovum (egg) inside the ovule becomes the embryo plant (baby plant).
The calyx, corolla, stamens, stigma and style usually shrivel and fall off.
The ovary forms a fruit.
Examine the flowers of a plant and follow the fate of the different parts of the flowers until mature fruit forms.

9.6.9 Post-fertilization fate of the endosperm, shepherd's purse
See diagram 9.99.3: Shepherd's purse embryo
As the embryo develops it occupies a groove in the centre of the endosperm.
In exalbuminous (non-endospermic) seeds, legumes, the embryo absorbs the endosperm and food reserves are transferred to the large fleshy cotyledons.
In albuminous (endospermic) seeds, the embryo remains surrounded by the endosperm.

9.6.10 Succulent fruits, "true" succulent fruits, fleshy fruits
The succulent part of a "true fruit" is formed from the ovary wall
Experiment
Observe the complete fruit and longitudinal and transverse sections
Collect different fruit, slice each fruit transversely and longitudinally and determine the type of fruit.
9.6.10.1 Aggregate fruit, syncarp
9.6.10.2 Berry
9.6.10.3 Drupe
9.6.10.3 Cherry seed
9.6.10.4 False fruit, pseudocarp
9.6.10.5 Pepo, Gourd
9.6.10.6 Hesperidium
9.6.10.7 Hip
9.6.10.8 Pip fruit, stone fruit
9.6.10.9 Pome

9.6.11 Zygote development
The zygote forms a firm cellulose wall then divides transversely into a filament of three cells, called the pro-embryo.
The large cell nearest the wall of the embryo sac is the base cell that attaches the embryo to the wall.
The middle cell is the suspensor initial that divides transversely to form a short filament called the suspensor.
The uppermost cell is the embryonic cell.
As it is towards the centre of the endosperm, it is nearer its food supply and can divide frequently to form the greater part of the embryo.
The embryonic cell divides by a transverse wall and then by two longitudinal walls at right angles to each other, to form the octants.
Each octant then divides by walls parallel to the surface (periclinal), into an outer and inner cell.
The superficial layer later divides only by walls at right angles to the surface (anticlinal), forming the dermatogen, which produces the epidermis.
The inner cells divide periclinally, so that inner and outer series of cells are formed.
In the lower part of the embryo, this segmentation is much more regular than in the upper half the lower forms the hypocotyl and root, while the upper forms the cotyledons (seed leaves) and plumule, (terminal bud).
The central cells are the plerome, which produces the stele tissues, while the outer series is the periblem and produces the cortex.
The uppermost cell of the suspensor is the hypophysis, which forms the root apex by division.
Between the two cotyledons the small plumule arises at the base of the groove between them and terminates the hypocotyl.
The hypocotyl and radicle with its root cap, have all developed from the embryo initial and the hypophysis of the pro-embryo.
The greater part of the embryo, however, arises from the embryo initial.
In monocotyledons, a pro-embryo of three primary cells is formed as in dicotyledons.
However, only one cotyledon appears terminal on the hypocotyl, while the plumule arises laterally.

9.6.12 Zygote development, shepherd's purse
See diagram 9.99.1: Shepherd's purse embryo 1
See diagram 9.99.2: Shepherd's purse embryo 2
Experiment
Examine stages in the development of the embryo of shepherd's purse, Capsella bursa-pastoris.
Use a flowering shoot, freshly gathered, with a few flowers at the top of the raceme and a succession of fruits below.
Remove ovules from a fruit that has a size about one third of that of a mature fruit.
Place these ovules in a drop of 1% caustic potash until they become transparent, cover and examine the campylotropous ovule.
(campylotropus: micropyle of curved, inverted ovule almost touches funiculus)
Press gently on the coverslip to cause the embryos to escape from some ovules.
Irrigate with dilute acetic acid, so make the embryo walls more apparent.
Examine the embryos squeezed out from the ovules of both older and younger fruits.

9.7.1 Buttercup flower,
Ranunculus ficaria, Ranunculaceae, Buttercup family
See diagram 9.3.2: Buttercup flower
Experiment
Observe the number, arrangement, shape and colour of each set of organs, i.e. sepals, petals, stamens and carpels, then dissect the flower.
Observe the five separate petals that are yellow, sometimes white.
Observe that the sepals are pale green, boat-shaped, and covered, on the outside with hairs.
The petals are yellow, larger than the sepals, heart shaped, and each bears a nectary at its base as a cup-like scale at the base.
Buttercup flowers have numerous stamens with slender, yellow anthers surrounding the green centre.
Each stamen is divided into two main portions, the filament and the anther head, whereas the carpels are free and each is composed of an ovary, a style and stigma.
That green centre is composed of a cluster of several distinct, unconnected pistils, which will develop into small, dry achenes.
Experiments
Draw a half flower diagram to show the relative positions of the various organs of each whorl as they are set upon the receptacle.
Draw a longitudinal section to shows only those organs through which the scalpel passes when cutting the flower longitudinally.
Record the floral formula.

9.7.2 Chilli flower
See diagram 54.9.2: Chilli flower.
For this lesson you will need chilli flowers, one for two students, and razor blades.
You will also need a chilli fruit.
Before the lesson, practice cutting a half flower.
To do this hold the flower upside down and cut down the middle of the stalk between two of the sepals and cut the flower in half.
Now check that the stigma, style and ovary are cut exactly in half.
You will need a magnifying glass to see all the ovules in the ovary.
Can you count them? Give a flower to each pair of students.
Name each part of the flower as you point to them.
Show the students how to cut a half flower.
Touch each part of the half flower.
Students should also touch each part of their half flower and tell you is name and function:
6. Stalk
5. Receptacle: platform for other parts
1. Sepals: protect flower bud
2. Petals: attract insects
4a. Stigma: female part, pollen sticks to it
4b. Style: pollen grows down it
4c. Ovary: pollen fertilizes it to form a fruit
7. Ovule: pollen fertilizes it to form seed
3b. Filament: part of male stamen, holds up anther part
3a. Anther: part of male stamen, produces pollen
8. Pollen: can fertilize the ovary and ovules to produce fruit and seed.
After fertilization, sepals, petals, stamens, stigma, and style usually die and fall off.

9.7.3 Cherry flower
See diagram 9.3.3: Cherry flower
1. The cherry flower has male and female flowering parts in one flower.
On the outside are the sepals, then the petals, then the male parts, the stamens.
The female part, pistil, is in the middle of the flower.
A flower that contains both female and male parts is called a hermaphrodite.
Experiment
Hold a cherry flower by the stem and detach all the individual parts with tweezers.
Begin with the outer parts of the flower and work inwards.
Finally, cut off the part of the stem in the middle of the flower.
Put similar parts in groups and arrange the groups on the table in the order in which you detached the parts from the flower.
The first group are the sepals.
They form the calyx that protects the bud before blossoming.
Observe their colour, shape and number.
The second group are the petals.
They form the corolla, protecting the inner parts of the flower and attract insects.
Observe their colour, shape and number.
The third group are the stamens.
Observe their colour, shape and number.
Use a magnifying glass to see a thin stalk, the filament, with an anther on top that contains the pollen.
The last part cut away from the stem is the pistil.
The pistil has of three sections.
The convex lower section, adjoining the stem, is the ovary, which merges into the style at the upper end.
The tip of the style is called the stigma.
2. Study a cherry blossom with the naked eye and then under a magnifier.
Experiment
Observe the following:
2.1 The small, green, outer leaves, called the sepals that form the calyx, which protects the flower bud before it opens.
2.2 The white petals that form the corolla protect the inner parts of the flower and attract insects.
3. The stamens, on and above the petals.
Each stamen consists of a small thin stalk, the filament, on which the anther is mounted.
The stamens are the male parts of the flower.
The anthers contain the pollen.
4. The pistil is in the centre of the flower.
It consists of three sections:
* The bulbous, lower section, which adjoins the stalk of the flower, called the ovary.
* The style is attached to the upper end of the ovary.
* The upper end of the style forms the stigma.
The pistil is the female part of the flower.
5. Observe how the various parts of the flower are arranged and are related to each other.
Separate all the parts of the flower at their points of attachment.
Use forceps, starting at the outside.
Put similar parts together on a black piece of cardboard.
Write the names next to the rows of the various parts of the flower.
Study other flowers in the same way, e.g. columbine, primrose, dog rose, snapdragon and apple blossom.

9.7.4 Poinciana flower
See diagram Poinciana flower
Poinciana has five sepals that are thick and green on the outside and red on the inside, five separate petals
(The upper petal is more showy.) 10 stamens, and an ovary like a bean pod.
Poinciana has five sepals that are thick and green on the outside and red on the inside, five separate petals
(The upper petal is more showy.) 10 stamens, and an ovary like a bean pod.
Poinciana Delonix regia, Daley's Fruit Trees.

9.7.5 Hazel flower, Corylus avellana, Betulaceae
See diagram 9.3.4: Hazel flower and catkin
The hazel flower is either male or female.
The male flowers are grouped in catkins, and the female flowers are in the buds with the clusters of red threads.
The two types of hazel flower are found on different parts of the same bush.
In the spring find a hazel bush twig with catkins, which are already flexible and loose.
Experiment
Hold the twig over a hard dark surface and hit the catkins with a glass rod.
The yellow dust that falls is pollen, so the catkins are male flowers.
The male parts of a flower are the stamens with filaments and anthers.
The female part is the pistil with ovary, style and stigma.
To see whether the male and the female parts are in hazel catkins use a magnifier to examine the most wide open catkin.
On the flexible stem of the catkin are very many small leaf-like scales.
They stand out from the stem of the catkin like small rooftops.
In addition to the catkins there are also buds on the twigs of the hazel bush with a bundle of fine red thread on their tips.
Use tweezers and a dissecting needle to remove the small leaves and the scales, which enclose the bud.
Inside there are several green scale-like small leaves.
To one side on the lower edge there are two small egg-shaped structures, the ovaries.
The style and stigma of these ovaries are divided and are the red threads that jut out from the bud.

9.7.6 Hibiscus flower
See diagram Hibiscus flower
Hibiscus flower is a large red flower with five sepals, five red petals, many stamens attached to a red tube separate from the style that is inside it, five stigmas and so five female parts.
The flower does not usually produce seed.
Hibiscus rosa-sinensis, hibiscus, Chinese hibiscus, rose of China, hibiscus flower, rose mallow, shoe flower, Chinese rose, japa, showy flower, stamens on central column, Malvaceae
Hibiscus species, Daley's Fruit Trees.

9.7.7 Lily flower
9.3.1 Carpels and ovules, lily
9.2.2 Pollen from stamens, lily
9.3.3 Fertilization, lily
See diagram 9.98.1 Lily flower
See diagram 9.98.9 Lilium anther TS dehisced
See diagram 9.98.8 Lilium anther
See diagram 9.9.10 Lilium pollen grain
1. Lilium has a deeply bilobed anther with each lobe containing two microsporangia, pollen sacs.
The wall of the pollen sacs contains a outer epidermis layer and an inner layer of nutritive cells, the tapetum, which transfers nutrients to the forming pollen.
Inside the microsporangia are many diploid microsporophytes, pollen mother cells.
Each microsporophyte divides by meiosis to form a tetrad of four haploid microspores.
Each microspore divides by mitosis to form a generative cell and a tube cell.
The microspore is now a pollen grain, the male gametophyte.
The generative cell divides to form to nuclei to fertilize the ovary and form the endosperm.
The tube cell forms the pollen tube.
Experiment
Examine specimens of a large simple flower, lily.
Count the stamens and observe how they are arranged about the central pistil.
Make large diagrams of the essential organs.
Label the parts of the pistil (stigma, style and ovary).
Label the parts of the stamen (filament and anther).
The end of the stalk on which the flower grows is called the receptacle.
At the base of the receptacle there are usually leaf-like structures that enclose the bud.
These are called sepals.
Above the sepals there is usually a ring of brightly coloured petals called the corolla.

9.7.8 Sweet potato flower
Sweet potato flower has five sepals joined, five petals joined to form a purple trumpet, five stamens attached to the petals, and female part.
It can form little black seeds.
See diagram: Sweet potato flower.

9.7.9 Willow flower
See diagram 9.3.7: Willow branch and catkin
Collect willow branches with catkins beginning to open.
Willows have two types of catkins:
1. oval-shaped or round and, pale to bright golden yellow and 2. oblong, cylindrical, greenish colour.
Experiment
Observe whether both types of catkin occur on one branch or on the same tree.
Study an oval-shaped catkin by cutting longitudinally with a razor blade and using a magnifying glass.
It contains many stamens, which sit in pairs on a hairy leaf scale (bract).
They form the male (or pollen) flower.
Study an oblong, greenish catkin by cutting longitudinally with a razor blade and using a magnifying glass.
Observe the many bottle-shaped greenish structures, the pistils (the female flower organs).
Each pistil sits on a hairy leaf scale (bract).
In the hazel tree male and female flowers are separate, but on the same bush.
Sex differentiated plants on which both male and female flowers are found on the same plant are called monoecious plants.
Sex differentiated plants in which the male and female flowers are found in different plants are called dioecious plants.
Some dioecious plants possess fruits that can be eaten, e.g. sea buckthorn.
Its fruits are very rich in vitamin c and give a pleasant tasting juice.
When a plant flowers differs between species.
Anemones, primroses, cherry trees and apple trees flower in spring.
Larkspurs, roses and carnations flower in summer.
Dahlias and chrysanthemums flower in autumn.
Christmas rose flowers in winter.

9.6.2.1 Capsule, dry dehiscent fruit
See diagram: Cassava capsule
See diagram 64.6.1: Cassava seed and fruit
A capsule is the most common fruit type that splits to release the seeds
A capsule has three or more carpels and it opens by pores or splits, e.g. Eucalyptus, Leptospermum, poppy, lily, pansy, violet, iris, snapdragon, cotton, castor oil, kapok, okra, rosella, cassava, sweet potato.
A dry fruit that opens to let the seeds out, e.g. Jacob's ladder, Pink dianthus, primrose, poppy, evening primrose, pimpernel, foxglove.

9.6.2.2 Follicle, dry dehiscent fruit
A follicle has one carpel and it dehisces (splits) along one margin only, e.g. oleander, Grevillea, larkspur Delphinium, columbine love-in-a-mist. milkweed, peony.

9.6.2.3 Legume, pod, dry dehiscent fruit
See diagram 9.72.1: Legumes
See diagram 9.72.2: Legume flower
See diagram 9.100.8: Legume pod, Fruit types
A legume, pod, has one carpel and it dehisces (splits) along both margins, e.g. legumes, pea, bean, lentil, acacia, peanut, cowpea, tamarind.
Pod: A dry fruit that opens on two sides to let the seeds out. e.g. legume (cowpea, wing bean, peanut)
A legume pod is a dry dehiscent fruit with many seeds.
The legume, pea, develops from a single carpel and splits along both margins.
When the pea fruit is ripe, both parts of the pericarp twist to throw the seeds some distance from the parent plant.
When squeezing open a pea pod, you find the many seeds, the peas, lying in a hollow space.
This is also the case with bean pods.
You call such a fruit pod a "fruit".
In legumes the seeds, peas or beans, are suspended in a pod.
With the bean plant, you eat either the entire fruit (green beans as soup, a vegetable or salad) or only the seeds (e.g. bean soup made from white, dried beans).
With the pea, you eat only the seeds in pea soup, green peas as a vegetable or peas pudding.
Some peas can be eaten whole including the pea pod and enclosed seeds.
In France these peas are called "mange tous" (eat all) peas.
Experiment
Examine about 1 kg of fresh-picked legumes, e.g. peas or string beans or other legumes.
Pick out the pods that are not completely filled.
Open these and compare them with fully filled specimens.
The abortive seeds are the remains of ovules that were not fertilized by pollen.

9.6.2.4 Lomentum, dry dehiscent fruit
A lomentum has one carpel and the pod is constricted between seeds so it breaks into one seed pieces, e.g. clover, Cassia, bird's foot trefoil, Desmodium, Laburnum, Sophora

9.6.2.5 Silique (siliqua), Dry dehiscent fruit
A siliqua (silique) has two united carpel which splits down both sides, septum membrane between e.g. Brassicaceae, wall flower, cabbage, honesty, radish, stock.
Silicula: shepherd's purse
See diagram 9.5.2: Fruit types, Dry fruits
1. The larkspur follicle splits along its ventral suture.
It is formed from one carpel and contains several seeds.
3. Examine different types of siliqua and silicule, e.g. wallflower, shepherd's purse, honesty.
These fruits are formed from two fused carpels, and are distinguished by the formation of a false septum.
Experiment
Observe how they split to expose the seeds.

9.6.3.1 Achene, dry indehiscent fruit
See diagram 9.100.10: Achene, strawberry
Achene: One carpel, one seed attached to a hard pericarp, e.g. buttercup, strawberry, rose, cashew, sunflower.
Plants in the family Asteraceae (Compsitae) produce achenes.
Use a magnifying glass to examine the collection of carpels of the buttercup, when they have ripened after fertilization, thus forming a collection of fruit.
Each fruit is an achene.
Dissect one and find the single seed enclosed.
Compare and contrast a ripe strawberry with the collection of buttercup fruits, e.g. sunflower, buttercup, clematis, coreopsis, dahlia, marigold, zinnia.

9.6.3.2 Caryopsis (grain), dry indehiscent fruit
See diagram 9.113.4: Maize kernel (caryopsis)
Caryopsis, "grain": single carpel so a single seed is tightly closed in the ovary wall, indehiscent, pericarp fused with thin seed coat, e.g. maize (corn), wheat.
The seed coat is fused with the fruit coat.
A caryopsis usually has 1. a carpel, ovary wall, pericarp and 2. a seed coat, testa, fused together, e.g. cereals, grasses, wheat, maize, rice.
9.6.3.2.1 Popcorn, pericarp of maize
Popcorn, pericarp of maize, Zea mays, subspecies mays, flint corn
Heat 3 tablespoons (45 mL) of high smoke point oil, e.g. canola, peanut or grape seed oil, vegetable oil in a 3-quart saucepan on a medium high heat stove until it is very hot, but not smoking.
Add three or four popcorn kernels to the oil and cover the saucepan.
If they pop then the oil is hot enough to add 1/3 of a cup of popcorn kernels and immediately close the lid.
Remove the saucepan from the heated stove and wait for 30 seconds to bring all the kernels to a "ready to pop" temperature.
Return the saucepan to the heated stove.
The kennels immediately start popping.
Shake the saucepan to avoid burning the kernels and move the lid slightly to allow steam to escape.
When the popping almost ceases dump the popcorn into a bowl.
As the kernel gets hotter, water inside the pericarp vaporizes to turn the starch into a hot gelatinous mass.
With increased internal pressure, the kernel explodes with a popping noise and the starch solidifies intro a fluffy white mass as it leaves the pericarp shell.
Examine any kernels that have not popped.
They usually are very small or have an unusual shape that interferes with the breaking of the pericarp.
The pericarp of popcorn kernels is four times stronger than regular maize kernels

9.6.3.3 Cypsela, dry indehiscent fruit
A cypsela has two carpels, like an achene, but it has an inferior ovary (buried in the receptacle), e.g. dandelion, sunflower, daisy.

9.6.3.4 Nut, single hardened achene, dry indehiscent fruit.
A nut has more than 1 carpel and a woody wall, e.g. chestnut, acorn, macadamia nut, hazel nut, hickory, (a peanut is not a nut!)
See diagram 9.5.2: Fruit types, Dry fruits
Experiment
Examine a hazelnut, partly enclosed in its leafy cup.
Examine the nut in detail and expose the seed.
Compare this fruit with that of the buttercup.
Salvis fruit like a collection of small nuts.

9.6.3.5 Samara, Dry indehiscent fruit
See diagram 9.5.2: Fruit types, Dry fruits
Part of the fruit wall of a samara forms a wing
Experiment
Examine a bunch of ash fruits.
Examine a single fruit and cut a longitudinal section of it, thus exposing the seed.
Examine a double samara of the sycamore.
Pericarp that forms wings, e.g. ash tree, elm, maple, sycamore.

9.6.3.6 Schizocarp
See diagram 9.5.2: Fruit types, Dry fruits
See diagram 9.100.10: Carpels fused together to form an ovary that splits when ripe, e.g. geranium, mallow, hollyhock.
The mature schizocarp splits into mericarps, individual carpels having a single seed.
In Umbelliferae fruits, e.g. coriander (Coriandrum sativum) the schizocarp is called a cremocarp with inferior ovary, is formed from two one-seeded carpels, which remain separate and form indehiscent mericarps.
See diagram: Coriander 1
See diagram: Coriander 2
See diagram: Coriander 3
Geranium has a splitting schizocarp
Examine the schizocarp of the hollyhock, and compare this with the other types of dry, indehiscent fruits.
Schizocarp of maple is two samaras. See diagram : Schizocarp of maple

9.6.10.1 Aggregate fruit (syncarp, multiple fruit, collective fruit)
See diagram 1.4: Screw pine, Pandanus, multiple fruit (drupes).
See diagram 9.100.10: Strawberry, rosehip.
Fleshy fruit from group of flowers, the inflorescence, e.g. mulberry, fig, pineapple, breadfruit.
Many fruits stuck together to form one fruit.
An aggregate fruit, syncarp, is a collection of several carpels from one flower, from fruiting flowers sticking together to form one mass, e.g. blackberry, breadfruit, custard apple, fig (syconium) jack fruit, mulberry, Pandanas, pineapple, raspberry, rose hip (achenes), screw pine, strawberry achenes).

9.6.10.2 Berry, succulent fruit, fleshy fruit
See diagram: Succulent fruits, Berry, Coalesced berry
See diagram 54.1: Chilli, fruit, germinating seeds
See diagram 9.100.3: Banana, Pineapple
See diagram: Plantain Banana
See diagram 58.1: Papaya fruit
The "stem" of the banana is a false stem (pseudostem).
Berry has fruit wall in two layers - thin outer tough skin layer, thick juicy inner layer.
A berry has more than two carpels and the pericarp is divided into: 1. skin, epicarp, 2. fleshy or fibrous mesocarp, 3. thin skin, endocarp, e.g. avocado, banana, capsicum, carambola (star fruit), chilli, coffee, cucumber, currant, date, eggplant, gooseberry, grape, guava, mangosteen, marrow, melon, papaya, passionfruit, pomegranate, pumpkin, snake gourd, squash, tomato.

9.6.10.2a Gooseberry
See diagram 9.5.1: Fleshy fruits, aggregate, berry, drupe, pome.
A gooseberry has many pips distributed in the fruit pulp and not enclosed in a core as with the pip fruits.
Fruits of this kind are called berries.
The fruit pulp of the berries is also surrounded by peel or skin.

9.6.10.3 Drupe
See diagram 9.100.4: Drupe, mango, coconut, pea.
See diagram 55: Cocoa.
See diagram 53: Coconut.
See diagram 53.7: Coconut fruit
See diagram 9.100.4: Drupe Legume.
Drupe: Fruit walls in three layers: outer thin, middle thick, inner very hard - called a shell or stone, e.g. coconut, mango, coffee.
Wall in three layers. [Drupe]
A drupe has one carpel above the receptacle.
The pericarp is the outer skin, epicarp.
The mesocarp is fleshy or fibrous.
The endocarp is hard and stony.
It encloses one seed, kernel, e.g. "stone fruit", almond, apricot, cashew, cherry, cocoa, coconut, coffee, mango, nutmeg, peach, pepper, plum, walnut (2 carpels).
Aggregation of drupes are blackberry, loganberry, raspberry.

9.6.10.3 Cherry seed
The fruit is a drupe.
The cherry has a seed with a very hard shell in the middle of the fruit called the stone.
The plum, apricot and peach are also stone fruit.
The name "cherry pip" is also used colloquially, but is not technically correct.
The stone of the stone fruits, like the core of the pip fruits, is surrounded by fruit pulp enclosed in a skin.

9.6.10.4 "False" fruit, pseudocarp, succulent fruit
See diagram 52.7: Breadfruit
See diagram 9.100.3: Banana, Pineapple
See Pineapple fruit - coalesced berries
"False" fruit, succulent fruits
The succulent part of a "false" fruit is not formed from the ovary wall, e.g. fleshy receptacle of an apple or fleshy axis of a pineapple, strawberry has achenes on the outside.

9.6.10.5 Pepo or gourd, Succulent fruit, fleshy fruit
Fleshy skin, leathery skin from inferior ovary, e.g. gourds of Cucurbitaceae, e.g. cucumber, melon, pumpkin, snake gourd.
Like a berry with a hard outer skin.
See diagram: Snake gourd

9.6.10.6 Hesperidium
Hesperidium: succulent fruit, fleshy fruit
See diagram: Orange, TS.
See diagram: Citrus x myeri, Meyer lemon.
A hesperidium is a berry with a tough aromatic rind
Citrus fruit: Like a berry with thick peel and oil glands.
A hesperidium has many fused carpels, with pulp and tough rind containing oil glands, e.g. citrus fruits, citron, grapefruit, kumquat, lemon, lime, orange, pomelo.

9.6.10.7 Hip, Succulent fruit, fleshy fruit
Fleshy fruit containing achenes e.g. rose hip
See diagram: Rose hip.

9.6.10.8 Pip fruit, stone fruit and berries
See diagram 9.100.3: Berry, pineapple, banana
See diagram 9.5.1: Fleshy fruits
Distinguish between:
1. the seeds that differ in size and number,
2. the fruit pulp, which can be juicy,
3. the peel or skin that has different thickness and may contain oil glands.
4. You eat the fruit pulp and the skin of pip and stone fruits, but not as a rule, the seeds.
With the berries, you usually eat the whole fruit.
Allocate fruits to these groups and note which parts of which fruits can be used for food.
Cut the fruits in half lengthways.

9.6.10.9 Pome, Succulent fruit, fleshy fruit
See diagram 9.100.5: Pome (apple)
See diagram 9.5.1: Fleshy fruits
A pome has a "core", the ovary, and a fleshy receptacle, e.g. apple, firethorn (Pyracantha), hawthorn (Crataegus), Medlar (Mespilus germanica), pear, quince.
You can bite into the fleshy receptacle of a ripe apple.