Burke: Lycopodium clavatum vs. Lycopodium dendroideum

	Lycopodium clavatum	Lycopodium dendroideum
	common clubmoss, elk-moss
Habit		From a subterranean horizontal stem with scattered erect stems; the erect stems much branched above the base and resembling a small conifer tree, the branches spreading outwards, sometimes loosely fan-shaped; stems leafy throughout.
Leaves		Needle-like, to 4 mm long, 6-ranked along stem. On horizontal side branches the leaves are arranged in two rows on top of stem, one row on each side of stem, and two rows on bottom of stem.
Spores		In one to several spore cones (strobili) at tips of erect stems; cones greenish to tan, 12-55 mm long.
Comments		In Hitchock & Cronquist\\'s Flora of the Pacific Northwest, this species is treated as Lycopodium obscurum. Current taxonomy splits L. obscurum s. lat. into three distinct species. The other two occur only in eastern North America. They can be differentiated by the leaf arrangement on horizontal side branches: L. obscurum s.str. has leaves in one row on top, two rows on each side in which the leaves are twisted and flattened, and one row on the bottom in which the leaves are much reduced, while L. hickeyi has leaves arranged in one row on top, two rows on each side, and one row on the bottom, in which none of the are leaves twisted-flattened, and the lower row leaves are not reduced in size. See Flora of North America for an updated treatment.

	Lycopodium clavatum	Lycopodium dendroideum
Identification notes		The much-branched tree-like growth form and the subterranean horizontal stems sufficiently distinguishes L. dendroideum from our other Lycopodium species. L. annotinum and L. clavatum have much less branched erect stems and the horizontal stems are above ground.
Habitat	Moist coniferous woods and swamps.	Woodlands and open brushy areas. In Washington, found mostly among rock or talus with thick moss or duff layers, often under brush or on edges of forest. At mid elevations in the mountains.
Distribution	Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east to Montana, also in central and eastern North America; circumboreal [WildflowerSearch map] [BONAP county map]	Occurring in the Cascades Range and in northeastern Washington; Alaska to Washington, northern Idaho, and western Montana, east across the northern U.S. and Canada to the Atlantic Coast: south in the Appalachians to North Carolina. [WildflowerSearch map]
Origin	Native	Native
Conservation status	Not of concern	Sensitive in Washington (WANHP)
Sibling taxa	L. lagopus	L. clavatum, L. lagopus
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, WA Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

From a subterranean horizontal stem with scattered erect stems; the erect stems much branched above the base and resembling a small conifer tree, the branches spreading outwards, sometimes loosely fan-shaped; stems leafy throughout.

Leaves

Needle-like, to 4 mm long, 6-ranked along stem. On horizontal side branches the leaves are arranged in two rows on top of stem, one row on each side of stem, and two rows on bottom of stem.

Spores

In one to several spore cones (strobili) at tips of erect stems;

cones greenish to tan, 12-55 mm long.

Comments

In Hitchock & Cronquist\\'s Flora of the Pacific Northwest, this species is treated as Lycopodium obscurum. Current taxonomy splits L. obscurum s. lat. into three distinct species. The other two occur only in eastern North America. They can be differentiated by the leaf arrangement on horizontal side branches: L. obscurum s.str. has leaves in one row on top, two rows on each side in which the leaves are twisted and flattened, and one row on the bottom in which the leaves are much reduced, while L. hickeyi has leaves arranged in one row on top, two rows on each side, and one row on the bottom, in which none of the are leaves twisted-flattened, and the lower row leaves are not reduced in size.
See Flora of North America for an updated treatment.

Lycopodium clavatum

Lycopodium dendroideum

Identification notes

The much-branched tree-like growth form and the subterranean horizontal stems sufficiently distinguishes L. dendroideum from our other Lycopodium species. L. annotinum and L. clavatum have much less branched erect stems and the horizontal stems are above ground.

Habitat

Moist coniferous woods and swamps.

Woodlands and open brushy areas. In Washington, found mostly among rock or talus with thick moss or duff layers, often under brush or on edges of forest. At mid elevations in the mountains.

Distribution

Occurring chiefly west of the Cascades crest in Washington; British Columbia to California, east to Montana, also in central and eastern North America; circumboreal

[WildflowerSearch map]

[BONAP county map]

Occurring in the Cascades Range and in northeastern Washington; Alaska to Washington, northern Idaho, and western Montana, east across the northern U.S. and Canada to the Atlantic Coast: south in the Appalachians to North Carolina.

[WildflowerSearch map]

Origin

Native

Conservation status

Not of concern

Sensitive in Washington (WANHP)

Sibling taxa

L. lagopus

L. clavatum, L. lagopus

Web links