ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
487 
B. CRYPTOGAMIA. 
Cryptogamia Vascularia. 
Anatomy of Vascular Cryptogams.* — M. P. A. Dangeard classifies 
the very numerous species of Selaginella into two primary sections, 
dependent on the arrangement of the leaves, — Homotropse, in which tho 
leaves are of one kind only, and are opposite or arranged in various 
phyllotaxes, 3/8, 5/13, &c. ; and Dichotropse , in which they are of two 
kinds, and are arranged in four longitudinal rows. These are then 
divided into a number of groups, according to the structure of the stem 
and leaves. 
In the stem of Lycopodium we find a collection of cauline bundles, 
corresponding in their origin and structure, and in their relationship 
with the leaves, with those of Selaginella ; they are united into a central 
cylinder either by their metaphloem only, or also by their metaxylem. 
Tmesipteris possesses a rhizome entirely destitute of leaves, which 
presents a transition to a true root. In the vascular bundles of the 
stem the metaxylem is not simply centripetal, it surrounds the proto- 
xylem, which gradually disappears, leaving a lacuna. 
In the stem of Salvinia the central cylinder is large ; the endoderm 
has here and there a tangential septum ; scattered through the central 
parenchyme are a few vessels, the largest of which are replaced by a 
lacuna ; the phloem is external, but passes insensibly into the central 
parenchyme which contains the vessels. In the Marsiliaceae the fibro- 
vascular system is more complicated, and the leaf attains a great 
development ; the vascular bundles of the leaves are surrounded by an 
endoderm. The structure is very similar in the Filices. 
In the Equisetaceae we appear to have an approach to the structure 
of Phanerogams. In several species a lacuna makes its appearance on 
the internal face of the bundle, and this leads directly to the ordinary 
collateral bundles of the Dicotyledones. 
Anatomy of Marattiaceae. f — The following are given by Dr. R. 
Kuhn as the more important results of a fresh examination of the 
anatomical structure of the stem of Marattiaceae, the species examined 
being chiefly Kaulfussia sesculifolia and Marattia fraxinea. 
Kaulfussia has a creeping dorsiventral stem, while that of Marattia 
is, when young, radiar and erect, passing over gradually into a fleshy 
tuberous stem. The vascular bundles of the stem and leaves of 
Kaulfussia , Marattia , and Angiopteris are really concentric, not bicol- 
lateral like those of leptosporangiate ferns, the phloem-portion surround- 
ing the xylem-portion ; there is no bundle-sheath. In the leaf-stalk of 
Marattia fraxinea is a peculiar joint which appears to serve as a motile 
organ, the sclerenchyme-fibres within it passing over into collenchyme. 
The mucilage-passages are of lysigenous origin, from the absorption of 
the cell-walls of adjacent cells ; the mucilage itself originates from the 
disorganization of the protoplasm of these cells ; there are no epithele- 
cells. The peculiar masses in the roots of Marattiaceae are the result 
of an infection by a fungus, similar to that of the Orchideae, and the 
* Le Botaniste, i. (1889) pp. 211-70 (3 pis.). 
f Flora, lxxii. (1889) pp. 457-504 (2 pis.), and lxxiii. (1890) pp. 147-50. 
