EvANS: TAXILEJEUNEA PTEROGONIA 135 
touch; that similar auricles (not mentioned by Stephani) are 
present on the leaves; that the thickenings in the cell-walls are 
sometimes better developed than he implies; and that surface- 
verruculae can almost always be demonstrated. Unfortunately 
this specimen is destitute of female inflorescences, but the evidence 
of variation which it exhibits serves to break down still further 
the distinctions between 7. martinicensis and T. debilis, and the 
writer has no hesitation in considering them synonymous. 
Another species which is clearly in need of further study is 
T. dissitifolia Steph.,* based on a specimen collected by Pére 
Duss on the island of Guadeloupe. This species is known to the 
writer from description only, and Duss states, in listing it, that 
his own specimen is lost. So far as the description goes there is 
nothing to distinguish T. dissitifolia from T. debilis as here de- 
scribed, and the writer is inclined to regard the two species as 
synonymous. In the absence of specimens, however, it is im- 
possible to reach a definite conclusion. 
The close relationship existing between T. debilis and the 
three other species treated in the present paper has already been 
emphasized. Perhaps the closest relative of all is T. jamaicensis, 
and it was with some hesitation that the writer decided to propose 
the latter species as new. Aside from the difference in the under- 
leaves, however, T. debilis is distinguished from T. jamaicensis 
by its dioicous inflorescence and by the constant absence of 
wings and teeth on the keels of the perianth. The dioicous in- 
florescence is of course associated with frequent sterility. Many 
specimens have been collected in which no trace of sexual organs 
can be detected and even in female material perianths are often 
lacking. In the case of T. jamaicensis the presence of perianths 
can usually be demonstrated by careful examination. 
SHEFFIELD SCIENTIFIC SCHOOL, 
YALE UNIVERSITY 
*Symb. Antillanae 2: 472. 1900. Not ‘‘Hedw., 1900, p. 472," as cited by 
’ Stephani in his Species Hepaticarum (5: 464. 1913). 
