of the Anatomy of the Genus Selaginella, Spr. 145 
its constituent bundles, each with an endodermis and pericycle ; 
a binary stele so divided occurs in Kraussiana , S. Galeottei , 
&c. ; two binary steles splitting into their constituent bundles 
occur in .S'. Lyallii This account (p. 1435 ) does not seem to 
harmonize with that given at p. 766 , where 5. Kraussiana is 
spoken of as bistelic, .S'. inaequalifolia as tristelic, and 5. Lyallii 
as polystelic. Van Tieghem also speaks of the bast as being 
interrupted opposite the protoxylem-strands, and a similar 
statement is also made by Strasburger (24). As a matter of 
fact the phloem-parenchyma is almost never interrupted 
(exceptionally so in the creeping axis of 6 *. spinosa ), and the 
sieve-tube layer only in some cases. Even in 5. Martensii , 
as has been pointed out by Janczewski, isolated sieve-tubes 
occur in the neighbourhood of the protoxylem. 
Bower, in a recent paper on the structure of the axis of 
Lepidostrobus (26), makes some observations on the cortical 
tissue of Selaginella , and comes to the conclusion ‘ that the 
trabecular development in Selaginella is a specialized and 
more definite example of that lacunar development which 
appears in such various forms and positions in cortical tissues 
of various other Lycopodinous plants,’ a conclusion with 
which I entirely agree. 
In the same journal I endeavoured (27) to trace the de- 
velopment and distribution of the silica, which was known to 
occur in the cortex of S. Martensii, and which I have been 
able to demonstrate in several other species. 
From the above summary it will be seen that our know- 
ledge of the anatomy of the stem of this genus has not 
advanced to any appreciable extent since the date of 
De Bary’s Vergleichende Anatomie , save perhaps in regard to 
the developmental origin of the layers, and what we owe to 
the careful researches of Janczewski on the nature of the 
sieve-tubes. That much yet remains to be done must be 
apparent to any one who has had the opportunity of examining 
types so divergent in anatomical structure as 5. spinosa , 
Braunii , and S. Lyallii . I do not profess to have exhausted 
the subject even of the stem-structure, but I hope the 
