ANGIOSPERM^E 



373 



growth of its base, the young plant may be forced deep down into 

 the earth ; and the first leaf to appear above the surface is the first 



FIG. 342. Allium 

 cepa, early stage 

 of germination. 

 (After BAILEY.) 



FIG. 343. Allium cepa, 

 sprouting seed ; a, 

 junction of cotyledon 

 and stem. (After 

 BAILEY.) 



FIG. 344. Allium cepa, later 

 stage of germination; the 

 tip of the cotyledon is still 

 held in the ground; e, the 

 second leaf. (After BAILEY.) 



foliage-leaf, and not the cotyledon. Where no endosperm is present, 

 the food substances are stored in the cells of the embryo. 



The primary root, although often well developed, is of limited 

 growth ; and soon others arise, so that a cluster of roots is developed 

 instead of the single A B 



tap-root commonly 

 met with in the Gym- 

 nosperms. 



Where the embryo 

 is well developed, as 

 it is in Naias or the 

 Grasses, the young 

 secondary leaves, and 

 sometimes the early 

 secondary roots, are 

 present in the unger- 

 minated embryo. 



The stem of the 

 sporophyte may re- 

 main short, as in 

 many bulbous plants, and in such cases the leaves when numerous 

 are closely set about the thickened axis. In the Palms and some 



FIG. 345. Yucca aloifofia. A, Cross-section of outer 

 part of the stem (X 4) ; cor, cortex; cam, cambium, 

 with young vascular bundles. B, a single young vas- 

 cular bundle (X 250). 



