IN CEYLON. 
5 
thirty-three species, and since they are not represented in the 
flora of Ceylon, they need not be considered here. 
The Brazilian genus Brachynema, Benth ., and the Javanese 
Drebbelia, Zoll ., are regarded by Hiern and others as being 
non-Ebenaceous, and as probably of Olacinaceous affinity. 
The five genera recognized by Hiern are so closely asso¬ 
ciated with one another that many botanists have suggested 
the advisability of uniting all into one genus. 
Hiern bases his classification of the genera mainly on the 
sex of the flowers, having the genus Royena with hermaphro¬ 
dite or rarely subdiœcious flowers ; the remaining genera, 
including Diospyros, with dioecious or rarely polygamous 
flowers. The observations were made upon material from 
the recognized herbaria of Europe, and a small quantity of 
spirit material obtained from Dr. Thwaites, Ceylon. 
As will be shown later, the sex of the Ceylon species 
of Diospyros has been imperfectly and often erroneously 
described as a consequence of examining only herbarium 
specimens instead of the fresh material in the jungle. 
The effect of Hiern’s admirable monograph is well seen 
if one considers the history of the development of our 
knowledge prior and subsequent to its publication. Since 
1873 but little has been contributed to our systematic 
knowledge of the Ebenaceæ, and from that time the ana¬ 
tomists have been at work on the basis laid down in Hiern’s 
monograph. Their investigations have resulted in more 
definite knowledge regarding the structure of the leaves, the 
secondary tissues of the stem, and the nature of the causes 
leading to the discolouration of the timbers. 
Wiesner* described the internal characters of the stems of 
some Ceylon species of Diospyros, and gave details of an 
onerous method of preparing sections of ebony, which was 
subsequently adopted by Molisch. His work was succeeded 
by contributions from Moeller,! in which the anatomy of 
* Wiesner, Ebenholz, 1870. 
f Moeller, Holzanat.. in Denkschr. Wiener Akad., 1870-8. 
