318 The Botanical Gazette. [June, 
has felt obliged not only to describe under a new name the 
common American species, but to modify the limitations of 
the genus as described by Cornu. 
In general terms Rhipidium Cornu may be said to be char- 
acterized as possessing a highly developed basal cell, attached 
to the substratum by rhizoids, which gives rise terminally to 
a number of filaments successively constricted and bearing sex- 
ual and non-sexual reproductive organs. The sexual organs 
consist of oogonia in which single oospores are produced as a 
result of fertilization by an antheridium, peculiar from the 
fact that it always penetrates the oogonium at a definite 
point on the surface of the latter. The sporangia are more 
or less oval in form and emit the zoospores in a cylindrical 
mass surrounded by a thin membrane which ruptures almost 
immediately, allowing them to escape. oe 
Such in general are the characters of the genus as origin- 
ally described; and in regard to the species, a comparison ’ . 
the scattered references which one finds in the ‘‘Monograph 
ng The 
g and 
twisted filaments and apply themselves near the base of the 
oogonium,* although in the figure given in Van Tieghem 
species in all respects except that the filaments are pate 
ous, the only constrictions present being those which sepa! 
long, attaining a length sometimes of a millimeter. ei rid- 
face of the oospore is, moreover, undulate, and the oe 
* Cornu, Mon 
Sig vl — l. c. pp. 15 and 103. 
5 Traité de Bot. 1024. fig. 617. 
