526 Sykes and Stiles. — The Cones of the Genus Selagihella. 
another in the most primitive group of the genus, by both Baker 1 and 
Hieronymus, 2 on the ground that neither species is dorsiventral. 
A section of the cone of an unknown species was found in a cabinet of 
slides at the Cambridge Botany School; unfortunately we have not been 
able to identify it. The sporophylls of this cone had a remarkably well 
developed free dorsal flap, relatively larger than that described in S. pumila , 
and quite solid without any air cavity. 
Type 2. The only other species examined which is not dorsiventral is 
S. spinosa . This form is also placed by Baker in his first group, along 
with the other non-dorsiventral species, but its many peculiarities make it 
difficult to regard it as primitive. 3 
Its cone differs from the cones of the other species in being cylindrical; it 
is very lax and is composed of large simple sporophylls with ciliate margins. 4 
The sporophyll is not folded round the sporangium growing in its axil, 
and hardly gives it any protection. The sporangium is thus exposed on 
a sporophyll which is almost flat (Fig. 5,^ and b> PL XLI), except for a slight 
depression into which the lower surface of the sporangium fits. There is no 
definite dorsal flap visible to the naked eye, but minute examination shows 
a very slight dorsal swelling, most prominent in the median plane of the 
sporophyll : the interior of this swelling is occupied by a small air cavity 
(Fig. 5 d t PL XLI). 
The megasporangia each contain four megaspores. The microsporangia 
are very large, much elongated laterally, and saddle-shaped (Fig. 5 c, 
PL XLI), recalling the sporangia of some of the Lycopodiums. There are 
occasionally a few lignified cells in the stalk of the old sporangia, but they 
are not present in the younger stages. 
At the base of the ligule is a cup of tracheides, similar to those recorded 
by Gibson 5 in the vegetative leaves of the species he examined. We did 
not, however, find this cup of tracheides in the sporophylls of most of our 
species. 0 
Types 3 and 4 (dorsiventral). Among the dorsiventral species a number 
of forms have been examined. Type 3 is somewhat isolated and is described 
first: the forms included in Type 4 constitute a series which appears to us 
to suggest that there has been a progressive change in the form of the 
sporophyll. From the complex sporophyll with its freely projecting dorsal 
flap, such as we have described in S. pumila , and such as is probably 
present in X. Lyalliil there have been derived sporophylls in which this free 
1 Baker, J. G., 1887. 2 Hieronymus, G., pp. 653-664. 
3 e. g. the absence of a foot in the embryo ; cf. Bruchmann on S. spinosa , 1897, with Pfeffer on 
S. Martensii , 1870. Gibson appears also to regard the extremely simple stele in S. spinosa as 
peculiar rather than primitive (1894, pp. 171-173). 
4 Gluck, H., 1895, p. 355. 5 Gibson, R. J. H., 1S96. 6 See Mitchell, G., 1910, p. 32. 
7 Figured by Hieronymus, G., in Engler and Prantl, i. 4, p. 708, Fig. 408, and referred to by 
Mitchell, G., 1910, p. 21. 
