of the A natomy of the Genus Selaginella, Spr. 1 5 5 
The epidermis is distinct and encloses a poorly developed 
hypodermis. The inner cortex has small intercellular spaces. 
The trabeculae consist of endodermal cells articulating with 
two united strings of parenchyma-cells gradually merging into 
the inner cortex. The pericycle is two layers deep at the 
margins of the stele, and three layered dorsally and ventrally. 
One or two layers of sieve-tubes occur dorsally and ventrally, 
but these elements are absent opposite the margins of the 
stele. Two or three layers of parenchyma separate the sieve- 
tubes from the xylem. 
7. Selaginella caulescens , Spr. Baker’s Handbook, No. 232. 
The arrangement of protoxylems in this large and well- 
known species approaches closely to that seen in 5 . Martensii , 
only the dorsal cord does not fuse so quickly with the 
adjacent marginal protoxylem. I have examined, in addition 
to the type species, the varieties japonica , minor , and argentea, 
and find no substantial anatomical differences between them 
and the type. There is a cuticle, epidermis, and thick hypo- 
dermis, a thick cortex of cells polyhedral in section, ceasing 
abruptly at the margins of the lacuna. A siliceous deposit 
occurs in some of the varieties, though not, so far as I have 
seen, in N. catilescens itself. Longer or shorter endodermal 
cells articulate with swollen chlorophyll-bearing cells on the 
cortical side. The pericycle is two to five layers deep, being 
thinner opposite the margins of the stele. There are a few 
crushed protophloem-elements within the pericycle. The 
sieve-tubes are arranged in one or two layers dorsally and 
ventrally, and are separated from the xylem by two to four 
layers of parenchyma. The metaxylem is abundant save in 
the horizontal axes, where it is small in amount or altogether 
wanting. 
8. Selaginella Griffithii , Spr. Baker’s Handbook, No. 237. 
This species is anatomically very like N. Martensii. 
There is a well-marked epidermis, four to five layers of 
stereome, merging gradually into a thick-walled cortex, sharply 
marked off internally by a siliceous deposit. The stele 
is simple, with two marginal protoxylems and a dorsal cord 
M 2 
