PITTIER PLANTS FROM COLOMBIA AND CENTRAL AMERICA. 437 



In my P. castilloides, which also differs much from all the other 

 species in t^e shape and size of its leaves, the segments of the male 

 perianth are quite free and narrowly unguiculate. We are in the 

 dark as to the characters of the male flowers in P. guianensis, P. 

 laurifolia, and P. markhamiana, and it is doubtful whether P. calo- 

 phylla has a monophyllous or polyphyllous perianth, although it is 

 reported as "4-partitus." 



In Olmedia caucana, described for the first time in the present 

 paper, the leaves are strikingly like those of Perebea marlcJiamiana, 

 and the only reason, in the absence of female inflorescences or fruits, 

 for placing the species in the first rather than in the second genus, 

 is that the perianths are clearly gamophyllous, the base forming a 

 narrow tube and the tips being divided into two (or perhaps later 

 into four) lobules. A surprise may be in store for the botanist who 

 shall first be enabled to investigate the female flowers of this species 

 or the male flowers of Perebea marlcJiamiana. Mr. O. F. Cook drew 

 my attention to the fact that, while in the other known female 

 flowers of Perebea the style simply branches into two short, pubes- 

 cent lobules, there are broad, leaf-like stigmas, with an undulate 

 margin, in the latter species. Should other characters in the male 

 flowers or in the fruits show such wide departure from those attrib- 

 uted to Perebea, there could be no hesitation in concurring in Mr. 

 Cook's suggestion to separate P. marlcJiamiana as a distinct generic 



type. 



As the situation now is, every species of the genus, but for one 

 or two exceptions, is so imperfectly described that the leaf is 

 nearly the only part on which an analytical synopsis can be sketched, 

 unless, as is to be hoped, there are better materials in the European 

 herbaria. 



The genus seems to belong exclusively to the Hylaea formation, 

 and its known representatives are in the Amazonian basin, in the 

 Guianas, and on the eastern side of the Isthmus of Panama. 



KEY TO THE SPECIES. 



Leaves and stipules very large, the first ones cordate; perianth 



4-phyllous 1. P. castilloides. 



Leaves more or less rounded or cuneate at base. 



Leaves subsessile, smooth, remotely dented; stipules rather 



large 2. P. guianensis. 



Leaves petiolate. 



Leaves entirely smooth. 



Style glabrous, branching into 2 thick, glabrous 



stigmas 3. P. laurifolia. 



Style hairy; stigmas rather long 4. P. xanthochyma. 



Leaves smooth above, more or less hairy beneath. 



Leaves minutely pubescent beneath 5. P. integrifolia. 



Leaves stiff -hairy beneath, serrate 6. P. markhamiana. 



Leaves scabrous beneath, entire 7. P. calophylla. 



