538 Cook : A Synopsis of the 



cm. long. The lowest segment is not divided at the tip but is pro- 

 duced into a slender hair-like seta, 6 or 8 cm. long, making it nearly 

 as long or longer than the next segment above. 



The normal segments are split at the apex to the distance of 

 from 2 to 8 cm. and the tips are usually markedly divaricate, 

 owing to the fact that the young leaves of this species suffer two 

 impressions from the bases of older leaves, one near the middle 

 the other near the end. The pressure causes the curvature of the 

 unopened leaves, which in turn causes them to split apart when 

 the leaf expands. 



Old leaves are smooth and glaucous on the lower side, but in 

 the younger state more or less remains of the delicate appressed 

 hairiness present on the lower surfaces of the newly opened leaves. 

 The lower surface is distinctly grayish and glaucous, but under a 

 lens it can be seen that this appearance is due to the presence of 

 numerous whitish points (stomata ?) among which are scattering 

 brownish spots of larger size, the nature of which remains a ques- 

 tion. 



The free stalks of the largest leaves attain 65 cm. in length 

 and are 2 cm. wide near the base, 1.5 cm. near the apex. The 

 cross section is lenticular above, but the upper surface becomes 

 flat toward the base. 



Young unopened leaves are covered near the base, both above 

 and below, with a scurfy white tomentum and the margin of the 

 ligule has a long white fringe. 



To avoid possible error it seems best to make separate entry 

 of the following notes on specimens which might be considered 

 quite distinct from the larger and normally mature form of Ponceana, 

 but which represent, it is believed, merely a somewhat depauperate 

 condition of that species, although leaves exactly comparable 

 were not brought home by our party. The specimens in question 

 were collected by Sintenis (no. 3500) on the south coast of the 

 island near Guanica and distributed from Berlin as " Thrinax 

 n. sp." 



The leaves are characterized by the narrow straight-sided seg- 

 ments which retain the same width (15 mm. or less) for about 11 

 cm. ; they are united in the middle of the leaf for about 8 cm. and 

 the apical tapering part is about the same length. Other species, 



