Linnaeus, Sp. Pl. 2: 1101. 1753.
Common club-moss, lycopode à massue
Horizontal stems on substrate surface. Upright shoots clustered, 0.6--1.2 cm diam., dominant main shoot with 3--6 branches mostly in lower 1/2. Lateral branchlets few and like upright shoots; annual bud constrictions abrupt, branchlets mostly spreading. Leaves spreading, often somewhat ascending in distal 1/3 of branches, medium green, linear, 4--6 X 0.4--0.8 mm; margins entire; apex with narrow hair tip 2.5--4 mm. Peduncles 3.5--12.5 cm, with remote pseudowhorls of appressed leaves, loosely branched into 2--5 alternate stalks, 0.5--0.8 cm. Strobili 2--5 on alternate stalks (if double, usually with stalks 5--8 mm), 15--25 X 3--6 mm. Sporophylls 1.5--2.5 mm, apex abruptly reduced to hair tip. 2 n = 68.
Fields and woods; 100--1800 m; St. Pierre and Miquelon; B.C., Man., N.B., Nfld., N.S., Ont., P.E.I., Que., Sask.; Alaska, Calif., Conn., Ga., Idaho, Ill., Ind., Ky., Maine, Md., Mass., Mich., Minn., Mont., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., Tenn., Vt., Va., Wash., W.Va., Wis.; Mexico; West Indies; Central America; South America; Europe; Asia; Africa; Pacific Islands.
Plants found in eastern North America have been called Lycopodium clavatum var. clavatum ; those in the western part of the range, which have been called L . clavatum var. integrifolium Goldie, are distinguished by early shedding of the characteristic hairs on the leaf tips.
Lycopodium dendroideum group