of the Anatomy of the Genus Selaginella , Spr. 157 
almost fill the lacuna. The stele is slender and consists of 
a pericycle of one or two layers of large cells, one or two 
layers of sieve-tubes, absent opposite the marginal protoxylems 
and not infrequently interrupted dorsally and ventrally as 
well. There are numerous protophloem-elements. The 
sieve-tubes are separated from the xylem by a single layer 
of parenchyma. 
12. Selaginella stenophylla , A. Br. Baker’s Handbook, 
No. 334. 
This species has the anatomical characters of S. suberosa. 
The sieve-tube layer on the dorsal side is frequently inter- 
rupted by parenchyma. The ventral layer is, however, con- 
tinuous. There is a small amount of silica on the inner 
cortex. The pericycle consists of one layer of large cells, and 
the parenchyma next the wood is two to four layers deep. 
In specimens in my possession the rhizophores are in the 
upper parts frequently replaced by normal leafy shoots. 
13. Selaginella viticulosa , Klotz. Baker’s Handbook. 
No. 358. 
This and several of the succeeding species, though 
differing much from X. Martensii in habit and general 
morphology, yet do not vary greatly from it in anatomical 
structure. 
The stem of 5 . viticulosa is rooted in the lower part, 
ascending and dorsiventral above, but is fundamentally the 
same in structure throughout. The stele is simple and 
ribbon-like, and the leaf-traces are inserted on the marginal 
protoxylems as in 5 . Martensii. There is one (sometimes 
two) dorsally situated protoxylems derived from the fusion of 
the adjacent marginal protoxylems of primary and secondary 
axes, the dorsal cord of one side not fusing with the adjacent 
marginal protoxylem until after the formation of a second 
dorsal cord from the fusion of a second branch on the opposite 
side. I cannot confirm Dangeard’s figure of the course of the 
protoxylems. (22. PI. XII, Fig. 1). 
The stem is on the whole quadrangular in section. There 
is an epidermis and cuticle, — the epidermal cells being thin- 
