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 genus Lycopodium. They grow mostly in woods, having 1-nerved evergreen leaves arranged in four or more ranks. Some of them make long strands, as the ground pine, and are much used for Christmas decorations. The spores are all of one kind or form, borne in 1-celled sporangia that open on the margin into two valves. The sporangia are borne in some species (Fig. 301) as small yellow bodies in the axils of the ordinary leaves near the tip of the shoot; in other species (Fig. 302) they are borne in the axils of small scales that form a catkin-like spike. The spores are very numerous, and they contain an oil that makes them inflammable. About 100 species of lycopodium are known. The plants grown by florists under the name of lycopodium are of the genus Selaginella, more closely allied to isoëtes, bearing two kinds of spores (microspores and macrospores).

(Lycopodium lucidulum.)

(Lycopodium complanatum).