of the Anatomy of the Genus Selaginella , Spr. 173 
The cortex of the erect axis is composed entirely of parenchyma, 
but in the procumbent portion one to three layers of scleren- 
chyma make their appearance. As Bower (27) has already 
pointed out, the inner cortex has well-marked intercellular 
spaces, and these are even more pronounced in the creeping 
portion. 
Where the procumbent axis bifurcates, the xylem first of 
all becomes constricted and the central protoxylem separates 
into two portions, each of which becomes enclosed by the 
metaxylem, then by the phloem, and finally by a one-layered 
pericycle. 
It will be seen from the above description, and from the 
figures, that the anatomy of the stem of S. spinosa is quite 
different from that of the great majority of the monostelic 
Selaginellas, and furnishes no evidence of close relationship to 
such types as 5 . rupestris and X. oregana , near which it is 
placed by systematists. 
D. Galeottei Type. 
37 . Selaginella Galeottei , Spr. Baker’s Handbook, No. 185 . 
At the extreme apex of either a primary or secondary 
axis two distinct protostelic areas occur which lower down 
differentiate into two distinct steles. At the region between 
the points of origin of branches each stele possesses one 
protoxylem group on the outer margin (PI. X, Fig. 41). On 
these the leaf-traces from the dorsal and ventral leaves of 
either side are inserted. At first the wood consists of proto- 
xylem only, but about 1 cm. from the apex scalariform tra- 
cheides make their appearance and ultimately form a bulky 
metaxylem. In younger branchings the two steles run distinct 
through the c articulation * (PL X, Fig. 40). The inner stele of 
the branch receives the axillary leaf-trace and then fuses with 
the inner stele of the axis, and lower down with the outer stele 
of the branch, running on as the marginal stele of that side of 
the axis beneath. Fusion of the pericycles of the steles takes 
place at the more apical branchings, but no metaxylem is 
developed until much later. In older stems the two steles of 
