Palms of Puerto Rico 555 



Acrista gen. nov. 



Trunk slender, of uniform diameter. Pinnae horizontal, ap- 

 pendiculate. Inflorescences distinctly infrafoliar ; spathes two, the 

 outer short, the inner long and slender. Spadix once-branched, 

 the branches coarse, tapering. Fruits with stigma lateral, seed 

 deeply ruminate, embryo basal. 



Related to Roystonea, but differing in the more slender habit, 

 the once-branched inflorescence, the basal embryo, and in having 

 the leaflets in one plane. The color of the foliage is also consid- 

 erably lighter than that of the royal palm so that from a distance 

 the general appearance suggests the cocoanut rather than the 

 royal palm. 



There is also some resemblance between the foliage of Acrista 

 and Cocops, but the absence of sheathing leaf-bases in the latter 

 genus will enable even young specimens to be separated. More- 

 over the leaf-divisions of Cocops are much narrower and those at 

 the end of the leaf are not so much shortened as in Acrista. 



Further differences from Roystonea are to be found, such as 

 the much smaller size and the larger roots, which are tuberculate 

 and inclined to become superficial like those of the Hume palm. 

 The sheathing leaf-bases are not as long proportionately as in 

 Roystonea, and there is a distinct formation of fibers, although the 

 texture is flimsy. The outer sheaths do not split off and fall away 

 as promptly as in Roystonea but several dead ones sometimes hang 

 from about the base of the crown. Although the sheath is longer 

 than in Acria the fibers are much better developed, there being 

 but a few membranous shreds in Aeria, and no distinct fibers 

 at all. 



Among the mountains between Cayey and Guayama many 

 summits are covered with the palma de sierra, probably in places 

 which have never been cleared. A few of the palms follow 

 down the steeper uncultivated ravines. From a distance the 

 crowns suggest royal palms but a closer view renders the difference 

 apparent. There is also no suggestion of the bulging trunk of 

 Roystonea. In height the palma de sierra probably does not ex- 

 ceed the royal palm. 



The tips of leaflets of young leaves are connected by two brittle 

 red strands both of which lie on the mesial face, one along the 



