Horticulture Principles and Practices

FIGURE 2–14 A pome, represented by apple
(Pyrus malus.) (Source: George Acquaah)
FIGURE 2–15 A legume or pod, represented
by garden bean (Phaseolus vulgaris).
(Source: George Acquaah)
FIGURE 2–16
capsule.
A silique and a
Central membranous
partition on which
seeds are borne.
Cross section
(a) Silique
Outside covering
(b) Capsule
In others, seeds exit through holes near the top of the capsule, such as in lily
(Lilium spp.), iris (Iris spp.), and poppy (Papaver spp.).
b. Indehiscent fruits. Some indehiscent fruits may have a hard pericarp
(exocarp + mesocarp + endocarp). This stony fruit wall is cracked in order
to reach the seed. Such fruits are called nuts, as found in chestnut (Castanea
spp.), hazelnut (Corylus spp.), and pecan (Carya illinoensis) (Figure 2–17).
Nuts develop from a compound ovary. Sometimes the pericarp of the fruit
is thin and the ovaries occur in pairs, as found in dill (Anethum graveolens)
and carrot (Daucus carota). This fruit type is called a schizocarp. In maple
(Acer spp.), ash (Fraxinus spp.), elm (Ulmus spp.), and other species, the
pericarp has a wing and is called a samara. Where the pericarp is not
winged but the single seed is attached to the pericarp only at its base, the
fruit is called an achene. Achenes are the most common indehiscent fruits.
Examples are the buttercup family (Ranuculaceae) and sunflower. In cereal
2.3 Other Classification Systems (Operational) 49