1907-8.] Morphology of the Cone of Lycopodium cernuum. 363 
the persistent peripheral tissues in one or other of these three planes 
of section. 
So far as is known, the cone of L. cernuum is the most complicated in 
the genus Lycopodium. The biological interest of the very complete pro- 
tection afforded to the sporangium by the pads of mucilage which bound 
it on all sides except at the small distal opening, is obvious in the case of a 
plant flourishing in exposed situations in the tropics. A similar result is 
obtained in the case of L. inundatum * where, however, the sporophyll-bases 
are not coherent, and in varying degrees in other species. In L. cernuum 
alone, so far as is known, does the mucilaginous change extend to the surface 
of the leaf-base and render the sporophyll, as seen in accurately median 
section, distinctly pseudo-peltate. Sporangia inserted at a greater or less 
distance from the axis are found in L. carolinianum, L. clavatum, and some 
other species, but this feature is never so marked as in L. cernuum. The 
extension of the sporangium between its place of attachment and the axis of 
the cone is also a distinctive feature of the latter plant. 
The special interest attaching to the cone of Lycopodium cernuum 
lies in the light which it appears to throw on the morphology of the cone 
of Spencerites and on the affinities of that plant. The comparison may be 
for the present confined to S. insignis, the better known species, and it 
will suffice to refer generally to the works of Williamson, f Scott ,J and 
Berridge § for the descriptions and figures of the cone. 
In Spencerites the cone consisted of an axis bearing sporophylls which 
were usually arranged in alternating whorls. The sporophyll is thus 
described by Dr Scott ( Progressus , p. 170): “The sporophyll in S. insignis 
consists of a narrow pedicel bearing an upturned lamina with a dorsal lobe ; 
at the base of the lamina is a massive ventral outgrowth to which the 
distal end of the sporangium is attached by a narrow neck.” Elsewhere 
the sporophyll, owing to the extension downwards of the “ dorsal lobe,” is 
described as peltate. All these points are well represented in the recon- 
structed radial section given in Miss Berridge's paper, which also shows the 
small marginal appendage of the dorsal lobe. This figure should be com- 
pared with fig. 1 of the present paper. 
* Tlie relations between the sporophyll-bases and the sporangia in L. inundatum were 
described and figured by Gluck (Flora, 80, 1895, p. 359. PI. v. figs. 1-3), whose account I 
can confirm. The sporophyll does not possess the peltate form shown in Miss Sykes’ figure 
(loc. cit., text-fig. 5). This invalidates the argument advanced on p. 54 of her paper in 
favour of the L. inundatum, type of cone being reduced from that of L. cernuum. 
t “j Organisation of the Fossil Plants of the Coal Measures,” Phil. Trans., Part ix., 1878 ; 
Part x., 1880 ; Part xvi., 1889 ; Part xix., 1893. 
f Phil. Trans., vol. 189 (1897), Ser. B., p. 83 ; Progress. Pei. Botanicce, Bd. I., p. 170. 
§ Annals of Botany, vol. xix. (1905), p. 273. 
