THE ALLIES OF SELAGINELLA RUPESTRIS IN THE 
SOUTHEASTERN UNITED STATES. 
By G. P. Van ESELTINE. 
INTRODUCTION. 
The rupestris group of the genus Selaginella, in so far as it is rep- 
resented in North America, has attracted the attention of several 
botanists, only two of whom, however, have attempted to analyze the 
group as a whole. Underwood published,’ in 1898, a paper on 
“ Selaginella rupestris and its allies,” in which he called attention to 
the rich variety of forms, described 6 new species, and redescribed 
S. rupestris (L.) Spring, the type of the group, together with 
S. tortipila A. Br. Two years later Dr. Georg Hieronymus, of Berlin, 
published? a large number of new species of Selaginella, including 
13 from North America previously involved in S. rupestris. In 1901, 
the same author gave a synopsis of the whole group,’ which, though 
very carefully prepared, was based unfortunately on a comparatively 
small number of specimens. With the exception of the redescrip- 
tion of S. cinerascens by A. A. Eaton, and a short paper by Doctor 
Underwood, describing 2 new species from the southeastern United 
States, there have been no further contributions to the knowledge of 
S. rupestris and its allies in North America. 
It is apparent, however, from the diversity of the abundant mate- 
rial in American herbaria, that there are involved a number of addi- 
tional species. The present series of papers, undertaken at the sug- 
gestion of Mr. William R. Maxon, is intended to survey the whole 
group of Selaginella rupestris, to amplify the older descriptions 
where it seems necessary, to describe such new species as appear, 
and to correlate all descriptions with as large an amount of material 
as practicable. In pursuance of the last-mentioned aim, the author 
has been greatly aided by the curators of the Gray Herbarium, and 
of the herbaria of the New York Botanical Garden and the Missouri 
Botanical Garden, who have generously lent for examination all 
1Bull. Torrey Club 25: 125. 1898. 
? Hedwigia 39: 290-820. 1900. 
5Engl. & Prantl, Pflanzenfam. 1*: 621-717. 1901. 
