178 Gibson. — Contributions towards a Knowledge 
not unlike that of S. convoluta, , separating into two steles at 
the branchings. The cortex of larger stems shows an inter- 
esting anatomical feature, viz. the presence of intercellular 
spaces lined by siliceous deposit (PI. X, Fig. 49). I have not 
been able to detect any silica in the lacuna itself. 
E. Inaequalifolia Type. 
43. Selaginella inaequalifolia, Spr. Baker’s Handbook, 
No. 220. 
It is one of the best known species of Selaginella , if for 
nothing else, on account of the number of times Sachs’ figure 
of the transverse section of the stem has been made use of in 
botanical text-books, a figure which is, however, by no means 
free from inaccuracies. Dangeard ( 22 ) professes ‘ ressortir les 
relations qui existent entre la disposition des phytons et la 
structure de la tige.’ He says that there are three steles in 
the stem : that entirely depends on where the section is 
taken; there may be as many as five, and in the primary 
portion of the creeping stem there is only one. The median 
stele Dangeard describes as having two marginal protoxylems 
and an anastomotic bundle : there are often two dorsal cords 
on the median stele. His description of the mode of origin of 
the steles and his figure, I have not been able to confirm. He 
remarks that the leaf-traces are inserted on the median stele : 
that is correct so far, but he adds ‘ exceptionellement sur l’un 
des cordons lateraux,’ without saying which of them (the steles 
are, moreover, dorsal and ventral, not lateral), and without 
noting that the axillary leaves are invariably inserted on the 
ventral stele, and that no leaf-traces are ever inserted on the 
dorsal stele. 
I have dissected out the entire stelic system of a primary 
shoot, after boiling in caustic potash. By this treatment the 
tissues are rendered clear, so that the xylem-bands may be 
seen with ease under a dissecting microscope. Great care in 
the dissection is necessary to avoid rupturing the connexion 
between the various steles (PI. X, Fig. 54). 
