THE GENUS DIOSPYROS IN CEYLON 189 
the dry zone species except D. me elanoxylon occur, and: of the wet 
zone — only two, D. Gardneri and D. sylvatica, have been” 
obser 
iDwelve out of the twenty species are endemic, and several of 
them are rare; D. Ebenum is the chief source of ebony in Ceylon, 
and the best ebony i is produced by the trees growing on rocky and 
well-drained soil. All the species assume an arborescent habit ; 
e is 
variably to be pellucid ; sometimes this character is not very con- 
spicuous, as in D. affinis; in se other species, particularly in 
Embryopteris, D, Ebenum, and D. Toposia, the translucent 
D. oppositifolia, and D. sylvatica. The species generally belong to 
the evergreen type, but the twigs of D. montana and D, ovalifolia 
~ become badepe leafless every year in a dry northern districts. 
The my of the secondary xylem is of the ordinary Naete 
ibionont fps he differentiation of the tracheal elements and 
fibres is remarkably uniform, but the parenchymatous tissues 
exhibit sufficient variation to allow the species to be grouped under 
different types. 
Numerical tables are given, exhibiting, for each species, the 
dimensions of the vessels of the tracheal elements in the twigs 
nd sapwood Sed ei their radial diameter, their tangential 
diameter and ; also the radial diameter and length ‘ot the 
siicaachs stint cleniiaiil in the sapwood ; the radial diameter of 
the fibres in the heartwood and sapwood respectively ; ; the radial 
diameter, tangential diameter, and vertical length of the vertical 
nd the horizontal medullary ray cells 
_— 
2 
Sd gg 
fe] 
oO 
— 
bee So 
m 
fo 
According to previous authorities the genus is Pisswnevliae 
usually by dicecious flowers, and only rarely a polygamous or 
moneecious condition has been recognized; but Mr. Wright has 
recently made careful examination of fresh material in the forest: 
and has proved that there is a departure from the diccious state 
in ten out of the twenty species in Ceylon. Speaking generally, 
monecious, polygamous and hermaphrodite conditions ha aving 
been found. The occurrence of hermaphodite flowers “een in 
doubt their non-existence in any of the Ceylon species, provid 
i i ide t e 
pa, 
D. ovalifolia, D. ‘om sie quasita a, and D. Toposia ; two species, 
D, acuta and D. a aLsiniie, are moneecious only ; five species— 
