Sik eine a a bea ce ed 
AND ANATOMY OF THE STEM OF LYCOPODIUM. 17 
Strasburger has treated of one or two features in the structure of Lycopodium. He 
begins (p. 458) by noting the similarity between the structure of the vascular cylinder 
in Lycopodium and Selaginella, and says that the “central cylinder of a Lycopodium 
may be regarded phylogenetically as a union of steles (similar to that found in 
Selaginella) aud as gamostelic.” This was written at a time when Van Tieghem’s stelar 
conceptions received general acceptance, but a similar view is put forward in the 
morphological portion of the * Text-book of Botany. From this view of the structure 
of the vascular cylinder in Lycopodium I entirely dissent, and an explanation is offered 
in the course of the paper of the development of the complex structure from a simple 
form found in the seedling, with which the union of schizosteles is quite incompatible. 
It cannot be said that the account of Lycopodium (13) which appeared in Engler and 
Prantl’s * Pflanzenfamilien’ has added much to our knowledge of the genus ; the figures 
(p. 579) showing four very different configurations are instructive, but require some 
interpretation which is not given in the text. The paper on Z. clavatum by David and 
Weber (11) did not add any new facts. Linsbauer's paper (12) is concerned mainly 
with details of histology. He separates the orthotropic forms from the plagiotropic, and 
suggests that in orthotropic species the vascular cylinder is comparatively small and the 
xylems are broken up ; the last point is quite in agreement with the writer's conclusions. 
In the * Annals of Botany’ Mr. L. A. Boodle (14) described two species of Lycopodium : 
L. volubile, Frost, which belongs to the dimorphic group and is characterised by a very 
definite series of parallel bands of xylem and phloem; and JZ. salakense, Treub, in 
whieh the xylems and phloems are intermingled, presenting an appearance similar to 
that described for L. cernuum below. 
Itis convenient to begin the discussion of the morphological structure of the Lycopods 
by considering first the essential characters of a well-known species, and to proceed from 
this to a comparative description of other species. Since Lycopodium clavatum is 
generally taken as a type for the genus, the salient features of that species are briefly 
indicated. 
LYCOPODIUM CLAVATUM, Linn. 
A feature that characterises most of the temperate species of Lycopodium is the 
plagiotropie habit, and this tendency is well marked in the case of L. clavatum. The 
plant is found creeping along the ground, either on bare slopes or in grass, although its 
original habitat would probably be in woods or on the outskirts of woods, where by 
uprooting of the trees the plant would find the necessary condition for the burial of its 
spores. It is found growing with xerophytie plants, and shows a structure which is 
well adapted to unfavourable environment. The stem attains a considerable length, 
often a metre or more; it sends out branches every few centimetres and these show the 
same plagiotropic tendency. The end of the shoot or branch is often nearly erect, but 
radial symmetry is not found after the very early so-called seedling stages of the plant, 
except in the strobilus and in the stalk below the strobilus. In accordance with its 
dorsiventral structure, the roots, which are produced irregularly at intervals, arise from 
the lower surface, the branches arise laterally, and the leaves, more particularly those 
E2 
