20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 98 



showing a remarkable regularity in the 6 pinnae of the first leaf- 

 blade, with fewer pinnae and the number less regular on the second 

 leaf. The antiligule is a constant feature, even on the first leaf, tri- 

 angular and sharp-pointed, 5 to 7 mm. long, of very thin texture and 

 soon turning brown like the tips of the bladeless sheaths. The first 

 sheath, about 1 cm. long, has little chlorophyll and soon dies, the 

 second sheath, 4-5 cm. long, being more persistent. The surfaces of 

 the seedling, including the bladeless sheaths, midribs, veins and 

 margins of leaves, are moderately beset with reddish-brown scales, 

 more abundant near the base and the tip of the leaf -segments than 

 in the middle. The outer sheath rises from a shallow, cup, about 

 2 mm. high, like that figured by Martius as the coleoptile of Euterpe 

 oleracea, the Brazilian assai palm now called Cutis martiana. This 

 organ is an outgrowth of the cotyledon, not a part of the plumule, 

 and lacks the longitudinal fibers that give the sheaths a ribbed appear- 

 ance in drying. A single primary root usually is surmounted by a 

 single secondary, close to the coleoptile, which splits on that side. 

 The roots are very slender and wiry, with many contorted lateral root- 

 lets and adherent patches of a dark-brown membrane, suggesting an 

 early surface layer that exuviates. 



CONTRASTING FEATURES 



The outstanding differences are the columnar, short-jointed trunk, 

 abruptly thickened at the base; the thicker, more indurated leaf- 

 sheaths ; the large fibrous antiligule ; the short, densely squamous 

 petiole ; the long rachis with numerous close-set pendent pinnae ; the 

 more compact and shorter inflorescence, with the basal joint strongly 

 crassate and expanded to encircle the trunk ; the close-set branches, 

 subtended by small bracts ; the crustaceous exocarp with the style per- 

 sistent, and mounted on a broad indurated frustum ; the irregular 

 mesocarp fibers ; and the broadly grooved seed, with a narrow short 

 raphe. 



The relative absence of a petiole in the adult stage of Rooscveltia, 

 the more compact and shorter inflorescences, and the harder shell of 

 the fruits, in comparison with Plcctis, may be taken to indicate less 

 definite specialization as a forest palm, and better adaptation to open 

 conditions than related palms that are natives of heavily forested 

 regions on the continent. The island flora is very limited, of course, 

 in comparison with that of the continent, including only a few kinds 

 of trees, and these doubtless recruited gradually, so that in former 

 times the palms may have had much more open conditions than in 

 the recent period. 



