312 PHARMACEUTICAL BOTANY 
SEED SrRuCTURE.—The average seed shows one or two SEED 
Coats that enclose an Empryo which fills the seed cavity; the 
seed is then termed exalbuminous, as in beans, peas and other 
leguminous seeds; or between the seed coat and embryo reserve 
food may be stored, and the seed is then termed albuminous, as in 
the cereals, castor bean, etc. The stored food in or around the 
embryo may consist of starch and protein (pea, bean), or starch, 
Chalaza 
4 -~-Endosperm 
a = Cotyledons 
Raphe---~ : 
x _ Plumule 
£. -~ Hypocotyl 
ee Eig - <<< Caruncle 
i 
1 
; B 
J 
i 
! 
Hilum 
Fic. 235.—Castor-oil seed Ricinus communis), an albuminous type. A, view of 
seed halved flatwise, showing surface of cotyledon and hypocotyl. B, longitudinal 
section at right angles to the surface of the papery cotyledons. (Mottier.) 
protein and oil (peanut), or oil and protein and active medicinal 
principle (castor and croton), or of hard reserve cellulose and 
protein (date, nux vomica, coffee, ivory-nut, palm-nuts). The 
seed coats, corresponding to those of the ovule, are one or two in 
number. If but one seed coat is present it is termed the SPERMO- 
DERM. If two are present, the outer one is called the Testa, and 
the inner one the TeGMEN. The testa, or outer seed shell, 
differs greatly in form and texture. If thick and hard, it is 
