276 ON SEEDLINGS 



longer than the cotyledons, and the latter are very small in 

 Muntingia, continuous with, and scarcely broader than, the 

 thick and fleshy radicle. 



A large number of genera have a copious endosperm 

 surrounding a slightly shorter embryo with broad, foliaceous, 

 and ovate or rotund-cordate, straight and flat cotyledons 

 which are foliaceous in germination. This group would 

 include Christiana, Columbia, Erinocarpus, Triumfetta, Helio- 

 carpus, Honckenya, Luhea, Glyphsea, Apeiba, Echinocarpus, 

 Tricuspidaria, and others. There is, however, some variation 

 even in the same genus, as in Elseocarpus and Aristotelia, 

 the cotyledons of which are flat in some species and un- 

 dulate in others. These latter lead to a third group in 

 which the embryo is not entirely flat but has the cotyledons 

 variously curved or bent. Berrya Ammonilla may be taken 

 as a type of this group. The seed is obovoid, pale brown, 

 much thickened and black at the chalaza, and contains a 

 copious, colourless endosperm, which becomes white and 

 swollen when steeped in water. The cotyledons are obovate 

 or orbicular in different seeds and deeply cordate at the base, 

 including the hypocotyl in the notch, five-nerved from the base, 

 the nerves giving off smaller branches ; from being longer 

 than the endosperm they are sharply curved or bent to one 

 side below the apex. They are, however, otherwise flat, 

 closely adpressed face to face till they come in contact with 

 the thickening of the chalaza, when they bend towards the 

 dorsal aspect of the seed. The hypocotyl and radicle together 

 are about twice the length of the blunt auricles of the cotyle- 

 dons, beyond which they project. A transverse section of the 

 seed shows that the cotyledons are sometimes at least slightly 

 incurved so as to be concave along the median line. Several 

 others may be placed in this group inasmuch as the embryo is 

 more or less bent. Entelea has the cotyledons nearly flat and 

 the radicle inflexed or but slightly bent ; the embryo of Spar- 

 mannia is plicate or nearly flat and straight ; in Corchorus it 

 is incurved ; and in Schoutenia the margins of the cotyledons 

 are involute. 



The above are scattered through different tribes, several of 

 them belonging to the Tiliese, in which the extreme limit of 



