CRASSULACE^: 513 



embryo is small and generally shorter than the endosperm, 

 but that of Crassula magnolieefolia occupies the whole of the 

 seed, and has plano-convex cotyledons. As a rule the latter 

 are very short and obtuse, while the radicle is also short, or 

 sometimes elongated and terete. 



The cotyledons in Sedum album are narrowly oblong, and 

 about equal the terete radicle in length. 



Seedlings. The cotyledons observed are all succulent like 

 the plants themselves, and vary in shape from broadly oval or 

 ovate to orbicular. Like the leaves, the cotyledons of Crassula 

 quadrifida are covered with glands secreting a white sub- 

 stance. They persist for a long time, attain considerable size, 

 and generally are very unequal. Cotyledon Silversii is not- 

 able for the fleshy rootstock it produces while the cotyle- 

 dons are still present. The first leaf is suborbicular with 

 a cordate base, and the second is cordate. The cotyledons 

 are rather unsymmetrical. Those of Sedum Ehodiola vary 

 considerably in outline from oval or ovate to obovate, are tri- 

 nerved and generally slightly emarginate. The first leaf 

 is spathulate and very much smaller than the cotyledons. 

 The two primary leaves of Sedum nicaeense are elliptic, suc- 

 ceeded by others that become gradually oblong and then 

 linear, and crowded owing to the non-development of the 

 internodes. Sedum crassipes shows a considerable amount 

 of evolution. The cotyledons are very small, and the first 

 four leaves roundly cordate, almost or quite entire, while the 

 ultimate leaves are linear, distantly toothed and densely 

 arranged on the fleshy stems. 



Crassula quadrifida, Baker (fig. 332). 



Primary root slender, tapering, with slender secondary rootlets 

 and most frequently supplanted by strong adventitious roots from 

 tlie base of the hypocotyl. 



Hypocotyl most frequently very short (in some cases almost 

 none), generally about 1-2 mm. long, succulent, glabrous. 



Cotyledons persistent and becoming foliaceous, succulent, glabrous, 

 pitted on both surfaces with gland-like organs secreting a white 

 substance, rotund, obtuse, shortly petiolate, most frequently very 

 unequal in size, green above, purplish beneath ; smaller cotyledon 



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