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1910] BRIEFER ARTICLES 219 
described species (fig. 6). The leaves appear in close succession on the 
flattened tip, leaving no evident internodal region. The development of 
the internode afterward is very rapid, causing a conspicuous shifting of 
the position of the sporangium (fig. 7). The rapid growth of the internode, 
combined with the unequal rate of growth of the two sides of the sporangium, 
causes the foliar structure to become axial. A change of position to this 
extent is not uncommon in other species of Lycopodium, but in L. pithyoides 
there is a continued inequality in the rate of growth, so that the sporangium 
eventually takes a position on the stem entirely distinct from the leaf. 
At maturity the sporangium is not disturbed if the leaves are pulled off. 
The development in this case is the reverse of that in most species of Selagi- 
nella, in which the sporangium arises as a cauline structure, but becomes 
foliar when mature; while in L. pithyoides it is foliar in origin, but cauline 
at maturity. 
The sporangia of L. pithyoides are very large, attaining a breadth of 
2-2.5mm., and resemble those of L. dichotomum Jacq., according to 
Bower’s description and comparison,? although Miss SyKEs’s drawing,3 
while suggesting a tendency in the sporangium to be cauline, does not indi- 
cate a very close resemblance in other points. The stalk is short and rela- 
tively slender, ranging from 12 to 18 cells in diameter in sections cut radially, 
and about twice that in the other diameter. The cells are elongated and 
thin-walled, with no corner thickening and no trace of lignification such 
as Miss Sykes has described in L. clavatum and other species. The 
- vascular strand of the leaf shows no tendency to approach the sporangium. 
- The leaf trace arises from the vascular cylinder 5-6 mm. below the spo- 
rangium, turning sharply upward and then making an outward bend as it 
approaches the leaf. 
The sporangia resemble those of L. dichotomum in the number of wall _ 
layers also. In the upper part of the sporangium there are usually four 
layers, but there may be even more owing to the irregularity in the arrange- 
ment of the middle layers (fig. 4). At the base of the sporangium the 
wall may consist of 6-8 layers. In a young sporangium (fig. 8) the order 
of division and the relation of the layers is very plainly seen, but in the 
older sporangia this regularity of arrangement is lost. The inner layer or 
tapetum is well defined as a dense, darkly staining layer. The tapetal 
- Cells do not show any tendency to become rounded on the inner face. In 
? Bower, F. O., Studies in = lees: of spore-producing members; Equi- 
Setineae and Lyieidinaie Phil. Trans. Roy. Soc. London B 185:516. 1894. 
3SyKEs, M. G., Notes on the ius of the sporangium-bearing organs of 
the Lycopodiaceae. New Phytologist 7:41-60. 1908. 
