Dendrolycopodium obscurum (L.) A. Haines (redirected from: Lycopodium obscurum)
Family: Lycopodiaceae
flat-branched tree club-moss,  more...
[Lycopodium obscurum L.,  more]
Dendrolycopodium obscurum image
From Flora of Indiana (1940) by Charles C. Deam
Very local. In addition to my specimens it has been reported from Lake, Montgomery, Porter, and St. Joseph Counties. One of my specimens is from a small colony at the base of a north beech slope, bordering a soft maple swamp, and the other is also from a swamp bordering a lake. My specimens are not typical and seem to be intermediate between the species and the var. dendroideum (Michx.) D. C. Eaton.


Indiana Coefficient of Conservatism: C =6

Wetland Indicator Status: FACU

Diagnostic traits: horizontal stems subterranean; stem below branches soft, leaves appressed; tips of branches flat, six ranked (four lateral, one on lower side much reduced); strobili (cones) sessile, 1-6 per shoot.

Horizontal stems subterranean. Upright shoots treelike, many branched, branchlets numerous and strongly differentiated; annual bud constrictions absent; leaves on main stem below lateral branchlets tightly appressed, needlelike, 3.5--4.5 X 0.6--0.7 mm, soft. Lateral branchlets flat in cross section, 6--9 mm diam.; annual bud constrictions inconspicuous. Leaves in 6 ranks, 1 on upperside, 4 lateral, ascending-spreading, 2.5--5.5 X 0.5--1.2 mm, and 1 on underside, much smaller than others, ascending; margins entire; apex lacking hair tip. Strobili 1--6 at tip of shoot, sessile, 12--60 mm. Sporophylls 3 X 2 mm, apex long, gradually narrowing. 2 n = 68. Rich hardwood forests and successional shrubby areas; 0--1600 m; N.B., N.S., Ont., Que.; Ala., Conn., Del., Ga., Ky., Maine, Md., Mass., Mich., Ohio, Pa., N.H., N.J., N.Y., N.C., R.I., S.C., Tenn., Vt., Va., W.Va., Wis.
Prostrate stems deeply subterranean, elongate, branched; erect stems scattered, simple below, freely branched above, to 3 dm, the main axis 2 mm thick, the branchlets terete or flattened; lvs numerous, shining, 6-8-ranked, linear-subulate, all alike or ±dimorphic, 4.6 נ0.8-1.2 mm, entire, firm, sharp-pointed; cones terminating some of the branches; sessile, 1-4 cm, 5-7 mm thick; sporophylls yellowish, broad-based, abruptly acuminate, with hyaline, inconspicuously erose margins; sporangia reniform, 1.5-2 mm wide; spores with the commissural faces more finely reticulate than the outer, otherwise as in no. 9 [Lycopodium annotinum L.]; 2n=68. Moist woods and bog-margins in acid soil; boreal Amer. and Asia, s. in e. U.S. to n. Ga., Ala., Ind., and Mo.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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