151 



sity. The Porto Rican fresh-water plants are, however, some- 

 what narrower and the cells are slightly larger. Adventitious 

 branches from the dorsal surface at the nodes are found in plants 

 from both regions, but are met with more frequently in those 

 from Porto Rico. 



Caloglossa Leprieurii, as commonly understood, has a wide 

 distribution, ranging northward from South America to the Hud- 

 son River, occurring chiefly in tidal rivers. As collected about 

 New York and at West Point, it is considerably narrower than the 

 type, but does not seem to differ otherwise. Specimens taken at 

 West Point were identified as " Delesscria Leprieurii " by Mon- 

 tagne himself according to a note by Professor J. W. Bailey in 

 the Columbia University herbarium. What has been believed 

 to be the same species has been attributed at various times to 

 New Zealand, Ceylon, Calcutta, and other distant parts of the 

 world. And three species of this genus, more or less resembling 

 C. Leprieurii, have been described from fresh water, viz., Calo- 

 glossa Beccarii (Zanard.) De-Toni, from Borneo ; C. Amboinensis 

 (G. Karst.) De-Toni, from the island of Amboina ; and C. Zanzi- 

 bariensis (Goebel) De-Toni from Zanzibar. As all the other 

 members of the family to which Caloglossa belongs are exclu- 

 sively marine, so far as is known, it seems fair to assume that all 

 the species or forms of this genus inhabiting pure fresh water 

 have had a marine origin in times comparatively recent from the 

 evolutionary point of view. Karsten,* in discussing his Am- 

 boina plant from this standpoint states that the streams in which 

 he collected it (at an altitude, often of " mehrere hundert Fuss" ) 

 have a rapid fall to the sea and offer a transition in salinity too 

 abrupt to be readily overcome. Therefore, instead of assuming 

 a direct wandering up-stream under conditions practically such 

 as exist at present, he suggests the possibility that the plant has 

 been lifted out of the ocean in the course of the elevation of the 

 island itself. In Amboina, an abundance of coralline blocks at 

 an altitude equal to that of the Caloglossa stand as witnesses 

 that an elevation of the island has taken place. Goebel, how- 

 ever, in discussing the biological relations of Bostrychia Moritziana, 



*Bot. Zeit. 49: 270. 1 89 1. 



