About Dendrolycopodium dendroideum (Michx.) A.Haines
Dendrolycopodium dendroideum (Michx.) A.Haines, synonym Lycopodium dendroideum, commonly called tree groundpine, is a North American clubmoss species. It belongs to a group of closely related species colloquially referred to as groundpine; these taxa were previously grouped together as a single species, Lycopodium obscurum. This species is native to Russia, as well as colder regions of North America: it is present in all Canadian provinces and territories except Nunavut, and in northern and east-central parts of the United States, including Alaska. The genus Dendrolycopodium is recognized in the Pteridophyte Phylogeny Group 2016 classification (PPG I), but is not accepted in other classification systems, which place this genus within the larger genus Lycopodium. Dendrolycopodium dendroideum grows best in humus-rich, sandy, moist soils that are not completely saturated. It is very closely similar to D. obscurum, differing in that its side shoots are round rather than flat in cross-section, and all of its leaves are the same size. Historically, this species and other related clubmosses were collected to use as decorative Christmas greenery. Overharvesting has harmed this slow-growing plant, which is becoming increasingly rare. The spores of this species were also collected as lycopodium powder for use in early photography, though this species was not the preferred one for this purpose.
