FRUITS AND SEEDS 187 
seed, there is no reason for the pericarp to dehisce. The 
whole fruit is distributed as a single seed, and germinates 
as a seed. For this reason many achenes are popularly 
called seeds—e.g., sunflower, buttercup, straw- 
berry-pips, corn-grains, etc. 
A nut is a dry indehiscent several-seeded 
fruit, which becomes one-seeded by abor- 
tion. The hazel-nut is derived from a two- 
chambered ovary formed of two carpels con- 
taining several ovules. In some cases nuts 
are enclosed in false envelopes developed 
from bracts—e.g., the acorn lies in a cupule, 
or cup, formed of a multitude of coalescent 
bracts (Fig. 84); the hazel is partially en- 
closed in a membranous cupule ; beech-nuts 
(mast) and edible chestnuts are enclosed, 
three together, in a spiny fleshy shell ee 
(Fig. 85). or AsH. 
2. Capsular Fruits.——These are dry, many- 
seeded fruits which split open to allow the seeds to 
escape. The dehiscence may take place in various ways: 
(a) By pores—e.g., poppies, snapdragon (Fig. 86). 
Fie. 84.—Noutr (Acorn) Fic. 85.—Fruit or EpisLE CHEst- 
oF OaKk-TREE. NUT. 
a, cupule. a, nuts ; 6, cupule. 
(6) By teeth, into which the top of the capsule 
separates—e.g., Lychnis, Silene (Fig. 87). 
(c) By lids—e.g., henbane, pimpernel (Fig. 88), plan- 
tain. t 
(d) By longitudinal splitting—e.g., willowherb, violet, 
bluebell, wallflower, Iris (Fig. 89). 
