INTRODUCTION. 
15 
LYCOPODIACEiE. 
(Comprises only Lycopodium .) 
Lycopodiaceaj, Br., Decan., Hook., Lindl., Burn . ; — Lycopodine.®, Swz. ; 
Lycopodeje, Spreny .; — Bivalvia, Hoffm . ; — Valvat.e, Web., Mohr . ; — 
Stachiopterides, Willd. 
STRUCTURE. — The Lycopodia resemble the Mosses in habit, the Ferns in 
vascular structure and foliaceous texture, and the Marsileacese in fruit. The 
stems are rigid, leafy throughout their whole extent, not subterranean, but 
upright or trailing along the ground, frequently to the distance of many feet, 
and throwing out short, stiff, smooth radicles wherever they touch the soil. A 
transverse section of the root shows the longitudinal ducts to be compressed 
into an axis. In the stem they are arranged, as in the Ferns, into various cylin- 
drical bundles, the centre of which is filled with a cellular tissue, looser than the 
remaining part ; the ducts in this order are flat spiral bands, minutely dotted. 
The stomatse on the cuticle of the leaves are very abundant, the cuticle itself 
being reticulated, not as in the Ferns, but into regular four-sided meshes. 
The thecae are sessile, in the axils of the leaves, of two kinds, one two-celled, 
opening at a longitudinal fissure, containing very fine smooth resinous grains, 
which are supposed by most botanists to be pollen, but by Professor Bindley to be 
abortive thecse. The other kind is three or four-valved, opening at a transverse 
line, and contains from three to five round, slightly tuberculated grains, many 
times larger than the preceding. That these are the true spores of the plant is 
evident from their germination, and Willdenow says that he has seen the smaller 
grains grow also ; if so, they likewise must be spores, but as they are so very 
different in size and appearance, it is supposed that some mistake has arisen. 
Mr. Salisbury, in vol. 12 of the “ Linnsean Transactions,” describes the germina- 
tion of one species, which presents strange anomalies, throwing out a radicle and 
plumelet, in a manner similar to the monocotyledonous plants, and yet appearing 
immediately afterwards with two leaves, which he represents as cotyledons. 
DISTRIBUTION. — “ The Lycopodiacese for the most part affect exposed 
situations on open heaths, or the summits and sloping acclivities of mountains ; 
although without altogether shunning more shady homes. L. selaginoides inclines 
to the most humid situations, growing frequently in the crevices of dripping 
rocks, about waterfalls, and in swampy ground, where water oozes from the sides 
of hills. L. inundatum occurs in analogous situations, on lower or more southern 
heaths and commons. The other four species choose drier dwelling places ; L. 
selago and alpinum bearing the rude exposure of the mountain summits ; and 
L. annotinum and clavatum being more frequent on the sloping acclivities than 
on the summits ; but none of these four are exclusively restricted to such 
situations. The order is pre-eminently boreal and alpine, only one species, 
