ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
223> 
B. CRYPTOGrAMIA. 
Cryptogamia Vascularia. 
Leaves of Selaginella.* * * § — Prof. R. J. Harvey Gibson has made a care- 
ful study of the comparative anatomy of the leaf in the various species 
of Selaginella. The various forms may be arranged under four principal 
types, viz.: — (1) the Martensii- type (36 sp.) ; the epiderm is dissimilar 
on the ligular and aligular surfaces of the leaf ; there is a mesophyll 
consisting of reticulate parenchyme ; (2) Braunii- type (3 sp .) ; the 
epiderm of both surfaces consists of elongated sinuous cells, and has a 
distinct palisade layer as well as reticulate mesophyll; (3) Galeottii- 
type (9 sp.) ; the epiderm of both surfaces is composed of quite or 
nearly similar cells with wavy margins, and is much elongated in the 
long axis of the leaf ; (4) Spinosa-type ( 3 sp.) ; resembles the last, but 
the leaves are similar and are arranged spirally. S . Lyallii forms am 
anomalous type. 
The distribution of the stomates is very variable in the genus, but 
they are more abundant, as a rule on the aligular surface. The epi- 
dermal ceils are of three types : — conical, elongated with square ends, and 
sclerotic warty elongated fibres. The mesophyll varies very greatly in 
amount and in the form of its cells. The vascular bundle is almost 
invariably of very simple structure. All the species which have the 
Martensii-type of leaf belong to the monostelic and tristelic series as 
regards stem-structure ; while those in which the two epiderms are 
similar have two laterally placed steles. 
Apogamous Reproduction in Ferns.j — Mr. W. H. Lang has endea- 
voured to determine the connection between apogamous reproduction in 
Ferns and the “cresting” of the frond. With N eplir odium filix-mas 
there appears to be no such necessary connection ; with Scolopendrium 
vulgare, Athyrium filix-femina, and Aspidium angular e, the results were 
more variable. A prolongation of the mid-rib of the prothallium, similar 
to that described in a variety of Scolopendrium vulgare , was observed 
also in a variety of Lasirea dilatata ; it also bore sporanges, isolated or 
collected into sorus-like groups, as well as arehegones and antherids. 
Opening of the Sporange of Ferns. — Herr C. Steinbrinck J de- 
scribes the phenomenon of the bursting of the sporange of ferns, by which 
the spores are scattered, as consisting of three processes, viz. — (1) the 
opening of the sporange by the folding of the membrane, the annulus 
first stretching and then bending outwards ; (2) the return of the annulus 
to nearly its original form ; (3) a final shrinking in consequence of the 
complete evaporation of the water contained in it. 
By the use of the same apparatus § as that employed in the case of 
Mosses, Herr J. Schrodt || shows that the bursting of the sporange cannot 
be due to the pressure of the air in the intercellular spaces, since it takes 
place equally under a receiver when the air has been almost entirely 
pumped out. 
* Ann. Bot., xi. (1897) pp. 123-55 (1 pi.). Cf. this Journal, 1896, p. 331. 
t Rep. 66tli Meeting, Brit. Ass., 1896, pp. 1019-20. Cf. this Journal, ante, p. 56. 
% Ber. Deutsch. Bot. Gesell., xv. (1897) pp. 86-90. Cf. this Journal, 1896, p. 538.. 
§ Vide infra, p. 224. ||. Tom. cit., pp. 100-6. 
