vS 



PHANEROGAMS, 



only of a small fusiform appendage between them ; and this structure is especially 

 striking when the embryo attains a very considerable absolute size in those seeds 

 which possess no endosperm, and the cotyledons swell up into two thick fleshy 

 bodies (as in Aesculus, Castanea, Quercus^ Fig. 407, Amygdalus, Victa Faba, Phase- 

 olus, the Brazil-nut, &;c.); but more often the cotyledons remain thin like shortly 

 stalked foliage-leaves of simple form (as in Cruciferae, Euphorbiacese, and Tilia, the 

 last with a three- to five-lobed lamina). Most often they lie with their inner faces flat 

 against one another (Figs. 404, 405) ; but are not unfrequently folded or wrinkled 

 and curved backwards and forwards (as in Theobroma with thick, Acer and Convol- 



FlG. 442. — Ricin7ts co7nntJ!nis ; I longitudinal section of the 

 ripe seed ; // germinating seed with the cotyledons still in the 

 endosperm (shown more distinctly in A and B), s testa, e endo- 

 sperm, c cotyledon, he hypocotyledonary portion of the stem, 

 7v primary root, iu' secondary root, x the caruncle, an appendage 

 of the seed characteristic of Euphorbiaceae. 



Fig. 405. — Vicia Faba : A seed with one of the coty- 

 ledons removed, c the remaining cotyledon, iu radicle, 

 kn plumule, j testa ; B germinating seed, s testa, / a por- 

 tion of the testa torn away, ;/ hiluni, st petiole of one of 

 the cotyledons, k curved portion of the axis above the 

 cotyledons, he the very short hypocotyledonary portion of 

 the axis, h the primary root, ivs its apex, kn bud in the 

 axil of one of the cotyledons. 



vulaceae, &c., with thin cotyledons) ; less often they are rolled spirally round one 

 another. 



The axis of the embryo beneath the cotyledons is generally elongated and 

 fusiform, and when of this shape is described in works on descriptive botany as the 

 Radicle. This fusiform body consists however in its upper and usually larger part of 

 the hypocotyledonary portion of the stem, and only the lower posterior terminal 

 piece, which is often very short, is the rudiment of the primary root (Fig. 406). The 

 rudiments of the secondary roots can sometimes be distinguished in the tissue of the 

 primary root (in Cucurbita, and according to Reinke in Impatiens). 



Germmalw7t generally takes place — after the testa, or in dry indehiscent fruits 

 the pericarp, has burst from the swelling of the endosperm or of the cotyledons them- 



