350 ON SEEDLINGS 



convex, with the radicle nearly on the opposite side of the seed 

 from the hilum. 



A very common type is represented by Strobilanthes cal- 

 losus which has orbicular nearly flat five-nerved and reticu- 

 lated cotyledons, deeply and unequally auricled at the base, 

 nearly concealing the radicle. The latter is terete and hi 

 its lower half curved round one edge of the cotyledons. The 

 seed is slightly and obliquely indented at its insertion on the 

 retinaculum. The cotyledons are shortly petiolate while yet 

 hi the seed ; but the strong auricles spread out and partly dis- 

 appear after germination. 



Euellia longifolia (fig. 577) differs from the last in having a 

 straight radicle and equal or nearly equal auricles. The flat 

 orbicular seed is not indented at the hilum, but is slightly 

 prominent at its insertion on the retinaculum. It is also 

 papillosely hairy round the margin, with hairs of a mucila- 

 ginous nature which swell in water. The seed of Eranthemum 

 leuconeurum (fig. 580) is rotund-ovate, flattened and unsym- 

 nietrical, with a slight indentation above the base on one side. 

 There is a little tubercle or elevation at the hilum, and the 

 testa is produced into a little sac at the base to accommodate 

 the radicle, which is not surrounded by the cotyledons. The 

 latter are minutely auricled at the base, trinerved and reticu- 

 late. This peculiar conformation of the seed gives the coty- 

 ledons a cuneate outline which becomes much more apparent 

 after germination. In the seedlings examined they were much 

 more symmetrical than while yet in the seed, and slightly 

 emarginate. 



Seedlings. The cotyledons in this Order are mostly if not 

 always large in comparison with the size of the seed and 

 foliaceous. Although always of simple types, they are exceed- 

 ingly varied in form. 



A somewhat frequent form, represented by Dip teracan thus 

 micranthus, has suborbicular emarginate trinerved cotyledons 

 shallowly but generally unequally auricled at the base. In 

 this instance the hypocotyl is very short ; and the first pair 

 of leaves are oval. The cotyledons of Ruellia barbadensis 

 are five-nerved but otherwise similar. Those of Hygrophila 

 longifolia are almost truncate at the base. The hypocotyl is 



