IN CEYLON. 
57 
hard testa and a copious horny endosperm, and many do not 
germinate until nine months after sowing. 
The material required for the study of the vascular system 
prior to the production of secondary elements is best obtained 
by allowing the seeds to germinate on sheets of blotting paper, 
which are always kept moist, or on porcelain dishes partially 
immersed in water and covered by a bell jar. 
If it is desirable to study the embryo prior to the appear» 
ance of lignification of the proto-elements, a convenient 
method is to first thoroughly dry the seeds until the testa 
begins to crack and then immerse them in water kept at 100° 
F. for some time. Seeds of D. Ebenum treated in this way 
provided excellent material, since the embryos completely 
emerged from the confines of the endosperm into the bath 
without being injured in any way. 
Development of tli© Seedling. 
When the primary root has attained a length of 2 or 
3 cm. the young curved hypocotyl appears above ground. 
The cotyledons are embedded within the copious endosperm, 
and together with the testa are still below the surface of the 
ground. Subsequently the hypocotyl shows signs of rapid 
growth, the collet area increases in thickness, and the hypo¬ 
cotyl becomes more strongly arched and sooner or later 
assumes an erect position, carrying at its apex the cotyledons 
or epicotyledonary leaves. In every Ceylon species of 
Diospyros and also Maba, the seedlings are of the epigeal 
type, though the mode of development in those species 
having very short hypocotyls is suggestive of a hypogeal 
habit. 
In a few of our species, viz., D. Ebenum, D. Gardneri, 
D. sylvatijca, and D. montana, the pair of opposite ovate 
cotyledons persist for many months and function as assimila- 
tory structures until an adequate system of epicotyledonary 
leaves has been established. In all such cases the epicotyle¬ 
donary leaves develop very slowly. This is true for seedlings 
8(1)4 (8) 
