INTRODUCTION. 
II 
Those occupy the upper part of each theca ; on the lower part of it are found 
much larger grains, generally supposed to be spores contained in membranous 
bags. The spores themselves, according to Sir J. E. Smith, are oval, rather 
pointed, and contracted in the middle. A curious circumstance is said to attend 
the germination of Pilularia, that, although the theca contains several bags of 
spores, yet it never produces but one plant, (at least thus it is stated in 
Lindley’s Nat. Sys. ed. 2, page 416.) Is this one of the numerous instances 
in which theory and practice are at variance, or is it a fact ? If the latter, may 
we not rather suppose the coriaceous fruit to be a single seed, its larger grains 
cotyledons, its smaller fccula ? As if to confirm this view of them, Mr. 
Lloyd, in a paper on the Marsileaceoe, read before the British Association, 1836, 
says, that they grow from a determinate point of their surface ; if so, they are 
true seeds or buds, and not spores. He agrees also with me, that the plants 
arc not furnished with spiral vessels. 
LYCOPODI ACE/E. 
( Comprises o?tly Lycopodium. ) 
Lycofodiace.e, Br., Decan., Hook., Lindl., Burn .; — Lycofodine.e, Swg. ; 
Lycopode.e, Sprentj . ; — Bivalvia, Hoffm . ; — Yai.vat.e, Web., Mohr .; — 
Staciiioptekides, Willd. 
STRUCTURE. — The Lycopodia resemble the Mosses in habit, the Ferns in 
vascular structure and foliaceous texture, and partly the Marsileacese in fruit. 
The Stems are rigid, leafy throughout their whole extent, branches not sub- 
terranean, 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 cylindrical bundles, the centre of which is filled with a cellular 
tissue, looser than the remaining part. Whether or not the ducts here and in 
th<j| other fern allies are really spiral vessels, remains to be proved, though 
there is little doubt that they are so, as true tracheae seem always to accom- 
pany stomatae, and in this tribe the stomata: 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 of fruit 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. The other 
other kind of Theca is three or four-valved, opening at a transverse line, and 
b 2 
