VAN ESELTINE—SELAGINELLA RUPESTRIS ALLIES. 165 
It is the plant with more slender stems and with leaves bearing no cilia in the 
dorsal suture that must be taken as the type of S. arenicola, since Underwood, 
in his description, emphasizes the fact that the plant is “slender” and makes 
no mention of the dorsal cilia, while he subsequently used the presence of 
these as a distinguishing mark of 8S. aeanthonota. Of the other two specimens 
cited by Underwood in his descriptions of the species, one (Gadsden County, 
Florida, Chapman, in 1840) is true S. arenicola; and the other (collected in 
the vicinity of Eustis, Lake County, Florida, July 16-31, 1894, by Nash, no. 
1449) belongs to the other species, 
Selaginella arenicola is readily distinguished from any other species by its 
nearly smooth megaspores, long adnate leaf base, and extremely slender stems. 
Harper’s no. 1860 is peculiar in having a somewhat laxer habit and more 
spreading leaves than most collections of this species. 
EXPLANATION OF PLATES 16, 17.—Selaginella arenicola. Pl. 16, the type specimen; 
Pl. 17, Specimen collected near Grandin, Putnam County, Florida, Harper 6, U. 8S. Nat. 
* Herb. no. 513489. Both natural size. 
8. Selaginella humifusa Van Eseltine, sp. nov. PLATE 18. Figure 65. 
Plants ascending, densely cespitose, 5 to 7 cm. high; rhizophores abundant, 
arising only from the base of the shoots; stems (including leaves) up to 2 mm. 
Fig. 65.—Details of Selaginella humifusa. a, Dorsal view of leaf; b, ventral view; 
ec, dorsal view of sporophyll; d, ventral view; e, commissural face of megaspore; 
f, outer face. From the type specimen. Scale 30. 
thick, rather lax, freely repeatedly branching at intervals of 3 to 6 mm.; pri- 
mary branches abundant, 3 to 6 cm. long, with abundant short branchlets 5 to 
20 mm. long, these with still smaller branchlets; ultimate branchlets up to 
5 mm. long, simple, divaricate; leaves 8 to 10-ganked, imbricate, slightly ap- 
pressed, in the younger stages pale green, in age becoming cinereous brown, 
thickish, chartaceous, minutely papillose-roughened, flat above, slightly con- 
vex beneath, sulcate dorsally in a median line up to the apex, narrowly deltoid 
from a short obdeltoid base, minutely 8 to 12-ciliate on the margins, bearing 5 
