302 ON SEEDLINGS 



in breadth and the shape of their apex according to the cor- 

 sponding variations of the seed. The general outline is 

 obovate or roundly obovate and emarginate, tapering gradu- 

 ally or suddenly into the moderately long petiole. Those of 

 I. fruticosa (fig. 235) are broadly, almost roundly, obovate, gla- 

 brous with hairy petioles, ciliate at the margin, and obscurely 

 trinerved with the lateral nerves incurved so as to join the 

 middle one in the notch. This notch, as has already been 

 observed, is due, at least partly, to the thickening of the 

 chalaza and the indentation of the testa at that part. There 

 can be little doubt, however, that it deepens by a subsequent 

 more rapid development of the parts on each side of the apex, 

 where the three principal nerves end in the water-gland. A 

 small or minute tooth is also observable in the notch. The 

 cotyledons of I. Balsamina (fig. 234) are also obovate, with a 

 tendency to be broadly ovate or oval, emarginate, slightly 

 narrowed towards the apex at times, more or less cuneate at 

 the base, and glabrous. They are three- or faintly five-nerved. 

 Five slender or indistinct nerves also occur in a species with 

 lilac flowers, and the lateral ones join the midrib in the rather 

 prominent notch. The lamina is obovate-orbicular, and 

 appears sessile from the fact that the petioles are erect and 

 closely applied to the stem throughout their length. The 

 cotyledons of I. tenella are very broadly obovate, emarginate, 

 and trinerved, while those of I. tricornis appear to be some- 

 what anomalous in being obliquely emarginate or shallowly 

 and obtusely trilobed at the apex and indistinctly one- to 

 two -nerved. 



A third and somewhat more complicated type occurs in 

 Linmanthes Douglasii (fig. 230), which evidently bears con- 

 siderable affinity with Tropaeolum, the type of the next group. 

 The cotyledons are roundly cordate, nearly always minutely 

 emarginate, and marked at the apex with a small black scar, 

 tipped with white, rather succulent, glabrous, convex above, 

 and striated with numerous broad, shallow, ridge-like veins 

 curving off laterally from the midrib. The petioles are 

 rather deeply inserted in the basal notch of the lamina, and 

 are broad at the base, sheathing the plumule. The hypocotyl is 

 stout and subterranean, so that here again there is a necessity 



