544 ON SEEDLINGS 



the inner membranous. The embryo is as long as the endo- 

 sperm and has two linear-oblong, plano-convex cotyledons 

 about twice the length of the superior radicle. 



Seedlings. The seedlings of three or four species of Ephedra 

 coming under my observation are very similar, the chief dif- 

 ferences consisting in the length of the cotyledons and the 

 primary leaves. During the germination of Ephedra altis- 

 sima the testa splits longitudinally and may or may not be 

 carried up by the cotyledons as they rise above ground and 

 straighten. The cupular process observed lying over the tip 

 of the radicle in the seed seems designed to fix the latter in 

 the ground during germination while the cotyledons rise up 

 free. It is then seen to form a tubular sheath surrounding 

 the base of the radicle and attached to the empty testa which 

 is by that means pinned to the ground. Sometimes the 

 attachment becomes broken and the testa is carried up on the 

 tips of the cotyledons where it sometimes remains for a con- 

 siderable time. The cotyledons are linear, emarginate, plano- 

 convex, erect, but often much undulated or twisted by unequal 

 growth or by their efforts to get out of the seed, slightly 

 connate at the base, 3-1-5-7 cm. long and 1-5-2-25 mm. 

 wide. The primary leaves are opposite, decussate, connate at 

 the base, and the first four pairs are often unequal in length 

 and vary from subulate to linear, similar to, but much shorter 

 than the cotyledons. The cotyledons of E. fragilis differ 

 but slightly from those of E. altissima, the chief distinc- 

 tions being that they are acute, straight and 5-7 cm. long. 

 The first node of the stem above the cotyledons bears three 

 leaves in a whorl. 



The cotyledons of Ephedra vulgaris (fig. 674) are linear, 

 slightly channelled above, 3-1 cm. long and 1 mm. wide. The 

 leaves are opposite and decussate, ovate, obtuse, connate at 

 the base, very small and scale-like, and being so from the 

 first pair onwards, they offer a marked contrast to those of 

 E. altissima. The stem has a jointed appearance like that of 

 Casuarina or Equisetum. The cotyledons of an unnamed 

 species of Ephedra from Afghanistan are linear, semiterete, 

 obtuse, grooved on the upper surface, slightly connate at the 

 base, and otherwise closely resemble those of E. vulgaris. 



