44 



NOTES ON DIPTEROCARPS. 



sm. cot. 



Z.ftai* 



Eig. 2. Seedling at the time when Fig. 3. Seedling at the time when 



the cotyledons have just been with- the whorl of leaves is expanding, 



drawn from the capsule. Z. cot. larger I pair the two larger of the four 



cotyledon; sm. cot. lesser cotyledon. leaves. 



The figures show how unequal are the two cotyledons: the 

 larger is markedly four-ridged on the back (figs. 2, 3, and 5) : the 

 lesser is only obscurely four-ridged and is sagittate-reniform is 

 outline. This inequality though very evident in Anisoptera. is yet 

 greater in some other genera of the order, e.g. Dryooalanops. 



During germination the petiole of the cotyledons elongates 

 only a little. Brand is and Gilg, in Engler's Pflanzenfamiiien, 

 III. 6, (1895) p. 242, from very imperfect knowledge stated that 

 great elongation is a character of the order, an error due to 

 familiarity with the genus Dipt ero carpus, where it occurs, and want 

 of knowledge of other genera. 



In several if not all of the species of Dipt erb carpus, the coty- 

 ledons do not function as green leaves in the nourishment of the 

 seedling and are not drawn out of the capsule. But in Anisoptera 

 eostata as well as in other genera the seedlings are greatly injured, 

 if the withdrawing is prevented, or if they do not reach the light: 

 for instance if the capsules are buried under the surface of the 

 ground, so that the cotyledons are imprisoned, the seedlings in 

 Anisoptera either die or languish; while the seedlings of Shorea, 

 of several species at least, under the same circumstances die. 



The cotyledons when they have been freed, and as the hypocotyl 

 completes its straightening, part and come to stand more or less 

 horizontally (fig. 6). Then from between them, the shoot pushes 

 out and bears four leaves in a whorl. These leaves are to be seen 

 in figure 3 with their faces folded together. The fifth leaf and all 



Jour. Straits Branch 



