STUDIES OF TROPICAL AMERICAN PHANEROGAMS— 
NO. 2. 
By Paut C. STanDLey. 
INTRODUCTION. 
The present paper is in continuation of a series begun in 1914." It 
contains descriptions of new species and taxonomic notes upon various 
groups of plants, but chiefly the Amaranthaceae, Allioniaceae, Mal- 
vaceae, and Rubiaceae, and the group of families formerly known as 
the Leguminosae. There are included descriptions of two new genera 
in the Malvaceae. 
The new species described are based chiefly upon the extensive col- 
lections obtained in Panama by Mr. H. Pittier. Study of the Panama 
collections shows very clearly the close alliance of the flora of the 
Isthmus with that of Colombia, as was to be expected. Quite unfore- 
seen, however, is its inclusion of certain genera which are character- 
istically Brazilian, a fact recently pointed out by Mr. Pittier.2 Two 
Brazilian genera, Cassupa and Stachyarrhena, are here reported for 
the first time from North America. Moreover, several of the species 
described as new have their closest allies in Brazilian plants. 
NEW CYPERACEAE FROM PANAMA. 
While working with the Cyperaceae of Panama, the writer discov- 
ered two apparently undescribed species, a Rynchospora and a 
Scleria, descriptions of which are published below. The Rynchospora 
is particularly interesting, being very unlike any species previously 
reported from North America. 
There are also included new combinations in Cyperus, Stenophyllus, 
and Calyptrocarya, which are necessary for properly listing the 
Panama Cyperaceae. 
Rynchospora argentea Standley, sp. nov. 
Tufted perennial; leaves 30 to 40 cm. long, 2 to 3 cm. wide, acuminate, narrowed 
at the base into broadly winged petioles, prominently nerved, scabrous on the margins, 
elsewhere glabrous, silvery white, especially on the upper surface, at least when dry; 
1Contr. U. S. Nat. Herb. 17: 427-458. pls. 24-31. 1914. 
2 Journ. Washington Acad. Sci. 5: 468-469, 1915. 
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