548 Cook : A Synopsis of the 



The position of the embryo is, perhaps, the most obvious dif- 

 ference between this genus and Gaiissia, but there are several 

 other significant discrepancies. Thus the flowers are arranged 3 

 or 4 in a row, very seldom 5 or 6. Three fruits develop from one 

 flower only exceptionally. The trunk is of more than medium 

 height, and the inflorescence is in reality infrafoliar, for although 

 the dead leaf-bases and midribs of the leaves are persistent and 

 support the long inflorescence, this condition is not comparable to 

 that of the cocoid and other really interfoliar inflorescences. 



Aeria attenuata sp. nov. Plate 45 



The tallest of Puerto Rico palms, probably attaining 30 metres 

 and upward. The trunk is supported on a mass of coarse roots 

 with spine-like projecting rootlets arranged in whorls. The sur- 

 face of the trunk is smooth with very faint annular impressions. 

 Near the ground the diameter is 12 to 15 cm. and increases up- 

 ward to about 25 cm. at about 3 m. above the base. Above 

 this swelling the trunk tapers very gradually and in tall specimens 

 is less than 7 cm. in diameter at the top. 



The sheathing leaf-base is only 20 cm. long. The leaves re- 

 main attached long after the rupture of the open side, but no fibers 

 are formed, the edges of the split side being fringed only with 

 brown membranous shreds. The petiole is rather short, round 

 and rigid and the rachis is prominently angled above. 



Segments of a rather firm texture and standing in different 

 planes, but all more or less upright or oblique to the rachis, seg- 

 ments from middle of leaf 2.3 cm. wide near the base, 3.8 cm. 

 long. The segments are set very closely together, especially the 

 proximal, and overlap each other in a succubous manner. Fresh 

 fruits deep orange in color and of an unsymmetrical oval in shape, 

 16 mm. by 12 mm., with a firm, fleshy outer covering 1.6 mm. thick, 

 adherent to the seed, the three persistent styles remain of the 

 same size and are located at the base of the fruit. 



The seed is flattened oval, 11 mm. by 9 mm., with a promi- 

 nent basal tubercle (hilum). The surface is brownish with a few 

 shallow impressed lines, but the albumen is white and uniform. 

 Flowers and ripe fruit were obtained at Vega Baja in December, 

 1 899 ; type specimen no. 1 040. 



