LEGUMINOS^E 391 



and simple, while the second and third are abruptly pinnate 

 with three and four pairs of small, oblong leaflets respectively. 



Two well-marked exceptions in this tribe occur in Amorpha 

 glabra and Indigofera hirsuta, which have oblong trinerved 

 cotyledons with a cordate or auricled base. The first four 

 leaves of Amorpha glabra bear only one suborbicular leaflet, 

 while the fifth and sixth are pinnately trifoliolate. All 

 have stipules at the base of the petiole and stipellse near 

 the base of the leaflets. The first two leaves of Indigofera 

 hirsuta are lanceolate and opposite, and succeeding ones 

 alternate. 



Tribe Hedysarece. Two w r ell-marked types of cotyledons 

 occur in this tribe as well as some remarkably abnormal 

 forms. In the species of Hedysarum the cotyledons are 

 rotund-obovate, very broad, fleshy, and opaque, with rather 

 obscure venation, and both very strongly directed to one side. 

 They owe their size and shape to that of the seeds, which 

 again is due to the interior of the one-seeded segments of the 

 lomented indehiscent fruits. In these respects Hedysarum 

 coronarium (fig. 281), H. capitatum, H. obscurum, H. den- 

 ticulatum, and H. flexuosum agree. The first leaf of H. flexu- 

 osum and H. capitatum is pinnate with five small lanceolate 

 and oblong leaflets respectively. The first three leaves of 

 H. coronarium are simple, entire, and orbicular to oval-oblong ; 

 but the third one is pinnately three- to five-foliolate, with 

 similar-shaped leaflets. 



In germination the radicle pushes itself through the end 

 of the lomentum or through one suture, while the cotyledons 

 make their exit by the other, as in H. coronarium (fig. 281) 

 and H. obscurum. The wall of the fruit in H. denticulatum 

 (fig. 279) is thin or membranous and reticulate, and the radicle 

 generally pierces one valve, while by the swelling of the coty- 

 ledons and the elongation of the hypocotyl the lomentum is 

 burst open and the upper valve pushed upwards, permitting the 

 exit of the seedling. The testa is frequently carried up on the 

 cotyledons, but the breadth of the latter and their increasing 

 size soon splits it open and gets rid of it. Whatever the mode 

 of exit of the radicle and cotyledons, the wall of the fruit nearly 

 always gets pinned to the ground while the seedling rises clear. 



