338 ROBINSON. 



v 10. EUGENIA Linn. 



This genus contains the great bulk of our Myrtaeeous 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 Eu g e nia, Jamboaa, and Bytygium, in accordance with the previous arrange- 

 ment by Bentham A Hooker as subgenera, under the same names, except that 

 Eiieugcnia was used by them for the subgenus containing the more typical species. 

 It is with Jambom and Syzygium that we have here chiefly to deal, Bugmia 

 proper being represented by only a few species. 



Between a typical -/(tinhorn and an equally typical Syzygiiim, 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 Byzygium, 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, arc, 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 genetically such species as E. opcrculata 

 and its very near Philippine ally, here described as E. claiisa. 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 pr ocee ding 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 Eueuf/ciiiti. 

 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 docs 8y*ygium 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. jambulana, 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. 



