524 Sykes and S/iles .— The Cones of the Genus Selaginella. 
described by Goebel 1 and Bower, 2 it always arises from stem tissue, but 
its first rudiments may develop either in the axil of the sporophyll, or some 
little way above the axil. In some species, indeed (e. g. 5 . pumila ), even 
the mature sporangium is never found in the axil of the sporophyll, but is 
always borne on the stem above the axil. 
The line of dehiscence of the sporangium 3 is perpendicular to its 
plane of symmetry. It extends for some distance down both sides of the 
sporangium, and, as the latter is slightly inclined towards the main axis, is 
cut twice by most of the tangential sections of the cone which pass through 
it (see Fig. 4, PI. XLI). 
There is a well-developed air cavity in the base of many of the 
sporophylls, a fact which does not seem to have been recorded before ; 
these air cavities appear to us to be of some interest in that they recall the 
mucilage cavities of Lycopodium and the parichnos of fossil genera. 4 
The sporophylls of some species are provided with dorsal outgrowths 
of a more or less pronounced nature. Heironymus 5 refers briefly to small 
projections or ‘ Ohrchen ’ developed at the base of the sporophyll in 
X. microcladus , &c., and Lyon 6 has figured a dorsal flap in S. rupestris, but 
even these isolated cases have not been described. 
We will now proceed to the description of the various types of 
sporophyll found in this genus. 7 
Type 1. The most interesting and complex type of sporophyll is that 
found in S. pumila. This species has its foliage leaves radially arranged, 
and there is therefore a presumption that it approaches the original primitive 
form of the genus Selaginella. The sporophylls form a compact cone, 
and are arranged in four rows ; the micro- and megasporangia are somewhat 
irregularly distributed, and are to a certain extent exposed between the 
sporophylls (Fig. 1, PL XLI). The macrosporangia appear regularly to con¬ 
tain four fertile macrospores ; the microsporangia are saddle-shaped. The 
stalk of the sporangium contains a few more or less distinctly elongated 
cells, whose walls are slightly lignified ; 8 this character, however, is by no 
1 Goebel, K., 1881, p. 697 ff. 
2 Bower, F. O., 1894, p. 522 ff.; also Hieronymus, G., in Engler and Prantl, i. 4, p. 655. 
3 Goebel, K., 1901, has described the method of sporangial dehiscence (also Organography, 
ii, pp. 580-2). See also Mitchell, G., 1910, pp. 25-39. 
4 See Hill, T. G., 1906. Hill points out that hitherto nothing comparable with a parichnos 
had been recorded in Selaginella (p. 270). 
5 Hieronymus, G., p. 654. 
6 Lyon, F., 1901, Fig. 124, PI. IX. 
7 A recent article on the strobilus of Selaginella (Mitchell, G., Ann. of Bot., Jan., 1910) has 
dealt with the questions of the relative distribution of the two kinds of sporangia in the cones of the 
different species, and has revealed some interesting points in connexion with spore dispersal, &c. 
The stelar anatomy has also been dealt with. The present paper was complete before the appearance 
of Miss Mitchell’s article, but we have tried to avoid repetition by cutting out such portions as are 
now merely confirmatory observations. 
8 Cf. Sykes, M. G., 1908 (2), L. serration, Fig. 2, PI. Ill, and L. clavatum, p. 48. 
