ROBINSON. 
338 
10. EUGENIA Linn. 
This genus contains the great bulk of our Myrtaceous species, and for many 
reasons, requires introduction. From a purely systematic standpoint, it is 
perhaps desirable to state the reasons for including all our species under a 
single genus, though it is superfluous to one whose chief experience has been 
Asiatic or Australian. From the time of Linnaeus himself, many attempts at 
subdivision have been made, many of these bringing together numbers of closely 
allied species. The most recent, that of Niedenzu, 7 divides the group into the 
genera Eugenia, Jambosa, and Syzygium, in accordance with the previous arrange- 
ment by Bentham & Hooker as subgenera, under the same names, except that 
Eueugenia was used by them for the subgenus containing the more typical species. 
It is with Jambosa and Syzygium that we have here chiefly to deal, Eugenia 
proper being represented by only a few species. 
Between a typical Jambosa and an equally typical Syzygium, the difference is 
great. The former has large flowers, the calyx-lobes are likewise large, the 
petals are free and fall separately, the disk is conspicuous, the filaments are long. 
The Syzygium, on the other hand, would have small flowers, with a calyx-margin 
truncate or inconspicuously lobed, the corolla would not be differentiated into 
petals but full as a single calyptra, the disk would be thin and the filaments 
short. Yet all these characters, except those drawn from the corolla, are, even 
superficially, matters of degree. Regarding the corolla, it may be added, that 
the calyptra, when fallen, is sometimes easily separable into distinct petals, 
sometimes not at all, and that in different flowers upon the same branch, some 
may have calyptrate corollas, while in others the petals may be free and out- 
spread before falling. Experience with the Philippine species seeming to indicate 
that they can be best divided into natural groups by the presence of large and 
distinct calyx-lobes, as contrasted by their absence or small size, this character 
has been used as an early basis of division in the key. This being prefaced, it 
would seem at least as natural to separate generically such species as E. operculata 
and its very near Philippine ally, here described as E. clausa, where the apex of 
the calyx falls as a preliminary to the opening of the flower in a single piece, 
from the remainder, constituting practically the whole of the group, in which 
nothing of the kind takes place. No such proceeding has even been suggested, 
on the contrary these species are so close to others that confusion has sometimes 
taken place, and a similar error in this paper has only been prevented by field 
study. 
It must be admitted that some of the Philippine species belonging to Eueugenia, 
are so superficially different from the rest of our species, that they seem at first 
sight generically distinct, but upon analysis the character upon which this dif- 
ference is based proves to be pubescence and not the natural one of solitary or 
racemed flowers. Indeed, this section seems to shade into Jambosa at one extreme 
as perfectly as does Syzygium at the other. Further, within these sections, 
there are groups of species more definitely separable from the others of the section, 
than the sections are from one another. 
For these and other reasons, the whole are here included within the one genus. 
One direction, along which it is proposed to make future investigations, is the 
nature of the seed. In E. jambolana, the cotyledons are thick and fleshy, occupy- 
ing respectively the apex and the base of the cell, closely applied but easily 
separated, and then distinctly showing the radicle. In other species, the cotyledons 
occupy the sides instead of the extremities of the cell, or are not easily separable, 
7 Pflanzenfam. 3 7 (1893) 78-85. 
