ihadowed more than ia i those in which the main filaments of the 



frond are plainly and are not concealed 1>\. .1 co in which the main 



filaments or mor.- or less obscured by the presence ol papillae or 



highl) appendages. Into the first division fall U.javensis, U. glaucesi 



. ('. orientalisy and U. explanata. In the second division are 

 on the one hand V. argentea, f ientalis and U. flabellala, with pseudo-parenchymatous 



ither hand U. papillosa with its subspecies subpapillata, U. indica, I 

 U verticillosa and Cl. Wilsoni, characterised by the presence ol 

 1 hi 51 species constitute the genus, as delimited in the present paper. 

 /ing morphological and geographical grouping might also be suggested 

 ,\ Main filaments of frond destitute of papillae and of lateral appendages 

 East (ndies. Wist [ndies. 



i '. favensis. 

 ( '. glaucescens. 



I '. or ientalis. I . conglutinata. 



U. explanata. U. cyathiformis. 



W Main filaments papillose. 



East Indies. 

 ( '. papillosa. 



U. papillosa var. subpapillata (sp. prop.?). 

 C. Main filaments bearing lateral appendages: 

 Lateral appendages monostichous, secund. 



East Indies. West Indies. 



/ \ indica. 



('. palmet ta. U. spinulosa. 



6) Lateral appendages subverticillately or subdistichously arranged in upper part of frond : 



West Indies. 

 U. verticillosa. 

 U. Wilsoni. 

 c) Lateral appen produced on all sides of the main filaments (often appearing to be 



distichous), capitate, pedicellate ; capitula simple or componnd, neven- with acute apices : 

 East Indies. West Indies. 



I ' . argentea. U. occidentalis. 



I '. flabellum. U. flabellum. 



From this distribution table it will be seen that only one of the species U. flabellum) 

 ommon to the Eastern and Western hemispheres. 



Another remarkable point which is of great systematic value is found in the relative 



the two constrictions above each dichotomy of the frond -filaments. These supra- 



dichotomial constrictions occur in all but three of the species [Cl. flabellum, f .verticillosa and 



ind are markedly uneven (see lig. 47) in the East Indian species with one 



