_Lycopodium clavatum._ Here the generic name is derived from two Greek words—_lukos_, “a wall,” and _pous_, “a foot.” One of the popular names of the plant is Wolf’s Claw; possibly an allusion to the curious branching-stem, although it must be confessed that the plant is not very claw-like. The specific name is derived from the Latin _clava_, “a club”; this having reference to the cones, or club, which bears the sporangia. The Stag’s Horn Moss, or the Common Club Moss. [Illustration: Lycopodium Clavatum. The Common Club Moss.] This species has wiry stems of considerable length, sometimes measuring as much as six or eight feet. These run along close to the soil, to which they are attached at intervals by strong roots. The stems which branch in all directions are covered with small narrow leaves, each of which ends in a curious little bristle. This gives to the whole plant a singular grey appearance. These hair-like points to the leaves may be regarded as a distinct feature of the Common Club Moss. In the autumn the fruiting spikes of the Common Club Moss are borne on the ends of erect stalks. The cones are generally about an inch in length, and at times as many as two or three of them may be allotted to each stalk. If closely examined it will be found that the fruiting spikes are composed of a number of leaf-like bracts, each one of which bears the case filled with spores. After the dispersal of the spores the cones fall off, but the plant as a whole remains green throughout the winter. The Common Club Moss is often very abundant upon the moors of the North of England, and also in Scotland and in Wales. On account of its creeping habit of growth the plant is often overlooked, and few people realize that this Club Moss is really very common. Sometimes single plants cover huge areas of ground, and many of the trailing stems are several feet in length. The spores of this, in common with those of other Lycopodiums, are inflammable; and in the old days these were used in the manufacture of fireworks. _Lycopodium selago._ In this case the specific name of _selago_ was that formerly given to all the Club Mosses. The Fir Club Moss.