Sporangium-bearing Organs of the Lycopodiaceae. 47 
complanatum with L. alpinum, he has connected L. volubile with 
L. cernuum. But an investigation of the sporangia and sporophylls 
by no means supports the last of these suggestions. 
L. volubile has a large axillary sporangium, on a stalk of medium 
length. The sporophyll is perfectly simple, it has no mucilage 
cavity, and resembles in many respects a sporophyll of L. dalhou- 
sianum or L. phlegmaria. In the sporangium pedicel, cells are 
present whose walls are lignified and pitted like those of the cells 
in a similar position in L. inundatum. As in that species, no 
connection can be traced between these cells and the vascular 
elements of the sporophyll trace; in many cases, how T ever, there is 
continuity between them and the elongated cells with lignified 
pitted walls which surround the trace and are continuous with 
similar cells surrounding the stele of the axis. Such continuity is 
also present in L. inundatum , but is not so striking. The line of 
dehiscence of the sporangium is in a position similar to that in 
L, inundatum , though not displaced quite so far onto the ventral 
surface. 1 
It appears to me that this species occupies a position 
intermediate between the phlegmaria group of the Urostachya and 
the inundatum group of the Rhopalostachya, and it might be to 
well to place it in a new group (iii.) Volubile , at the end of the 
Urostachya, thus making the inundata into group (iv). 
Groups (iv.), Cernua and (v.), Clavata. The species belonging 
to these two last groups agree in one important point, in which also 
they differ from all other species. This point is concerned with the 
position of the sporangium, which here does not arise in the axil of 
the sporophyll but takes its origin from the sporophyll stalk. An 
intermediate stage has already been described in L. carolinianum . 
It is found that the sporangium is slightly nearer the axil of the 
sporophyll in the young cones of L. clavatum and L. cernuum, than 
in the adult; (PI. III., Fig. 7). 
In the species of both groups, the sporangium is very efficiently 
protected, by means of a flap 2 which grows down from the dorsal 
surface of the abaxial region of the sporophyll, and thus it is not 
visible on the exterior of the cone (PI. II., Fig. 9a). The saddle- 
shaped appearance of the sporangium is very noticeable in all species. 
The sporophylls of Clavata appear to be less highly modified than 
those of Cernua and I will therefore describe them first. 
1 Engler and Prantl, Teil I., Abt. 3, Fig. 380, E F 
2 cf. L. annotinum, Goebel p 583 
