of the Anatomy of the Genus Selaginella, Spr . 163 
completely round the xylem, or Is interrupted only by one or 
two parenchyma-cells. 
The six succeeding species differ from those already 
described in the arrangement of the protoxylem-cords, and 
in the method of fusion of these. S . flabellata comes nearest 
to S'. Martensii ; the other five form their dorsal cords in 
a quite distinct manner. 
26. Selaginella flabellata , Spr. Baker’s Handbook, No. 245. 
A section of the stele of this species shows usually three 
to four dorsal protoxylems in addition to the two marginal 
strands. These dorsal cords are formed in the usual manner, 
viz. by fusion of adjacent marginal protoxylems of branch 
and axis. The fused cords, however, remain for a long dis- 
tance distinct from the marginal protoxylems of the axis 
beneath, although fusion between the dorsal cords themselves 
takes place (PI. IX, Fig. 19). The xylem is surrounded by two or 
three layers of parenchyma followed by sieve-tubes, arranged 
two deep dorsally, one deep ventrally and opposite the dorsal 
protoxylems, but absent opposite the marginal protoxylems. 
The sieve-tubes are wider on the dorsal than on the ventral 
surface. The pericycle is two layers deep. The trabeculae 
are normal, and a small amount of silica is deposited on the 
inner cortical cells. The surface of at least the older stems is 
covered by a plentiful development of unicellular cuticularized 
hairs. 
27. Selaginella atraviridis , Spr. Baker’s Handbook, No. 166. 
The arrangement of protoxylems in this and the succeed- 
ing four species differs considerably from that in S. Martensii. 
In the youngest branches the metaxylem is as usual not 
developed, its place being occupied by procambial tissue. 
The inner marginal protoxylem of the branch does not 
fuse with the adjacent marginal protoxylem of the chief axis, 
but runs quite distinct for a certain distance, and then fuses 
with the marginal protoxylem of the axis beneath, which 
latter is itself a downward continuation of the outer marginal 
protoxylem of the branch. Similarly the inner marginal 
protoxylem of the chief axis above the origin of the branch 
