AND ANATOMY OF THE STEM OF LYCOPODIUM. 25 
LYCOPODIUM CERNUUM, Linn. 
A more complex arrangement of the tissues was found in two specimens, both of 
which were assigned to £. cernuum, and this assumption was confirmed by Mr. J. G. 
Baker. The one specimen was brought to me from Singapore, and, although the material 
appeared to include two possible varieties, the general character and internal anatomy 
were similar throughout. A striking feature was the plagiotropic growth of the stem, 
which was similar to that of Z. clavatum; while the strobili furnished the clue to 
identification as cernuwm, and the vascular structure was most decidedly radial. 
The second specimen was part of the typically erect-growing plant, and agreed with 
the plant from Singapore in presenting an internal structure which at first sight recalls 
a Gleichenia (Pl. 3. fig. 6 and Pl. 4. fig. 27). The configuration is nearly, if not quite, as 
peculiar as that of L. salakense, Treub, which was described by Mr. Boodle (14). "There 
isa figure of the general structure in Engler and Prantl’s ‘ Pflanzenfamilien’ and a 
general plan is given (Pl. 4, fig. 27), as well as a photographic reproduction of the 
transverse section of the stem (Pl. 3. fig. 6). It will be seen that the xylems and 
phloems are entirely intermingled, and the phloem-islands often consist of only a few 
phloem-elements, or several phloem-groups may be connected together. The protoxylems 
are very broad. The branches show the same interspersion of the phloem-elements 
among the xylem, but the proportion of them is considerably less ; it was also interesting 
to find that the root presents a similar appearance to that of the branches. Another 
feature observed in the stem is the thickened area towards the outsideof the cortex ; this 
is very well marked both in the erect and plagiotropic shoots. 
In addition to the five species enumerated, L. dichotomum, Jacq., L. linifolium, Linn., 
and L. strictum, Baker, would appear to conform to the type of L. squarrosum. In 
L. dichotomum the configuration of the vascular cylinder is not so definite as might be 
expected; in the larger stems the cross-connections of the xylem-bands are sufficiently 
well developed to give rise to isolated patches of phloem, but in the branches the 
arrangement of parallel bands seems more obvious. Externally, L. dichotomum may be 
distinguished by the very definite areas which are marked by the leaf-bases. The stems 
of L. linifolium and L. strictum present a striking similarity to one another in their 
structure, which corresponds with that of L. nwmmularifolium. 
LYCOPODIUM CLAVATUM, L. Seedling Plants. 
Having outlined the general extent of variation which occurs in the structure of the 
vascular cylinder of various species of Lycopodium, it becomes a matter of considerable 
interest to endeavour to ascertain how this structure has been developed. Tt is entirely 
owing to the kindness of Dr. Lang that I can bring forward the following evidence, 
which is based upon the structure of the stem of young plants of L. clavatum, as he 
handed over to me several of the young plants which he obtained during his successful 
search for the prothalli of that species. Two of the youngest of these are shown in 
Pl. 4. fig. 28. The youngest plant (A), shown on the left, seems to have retained its 
radial symmetry. The stem-portion is connected up with the remains of the prothallus, 
but the first root is wanting, the roots which are shown being adventitious. The lower 
F2 
