Kingdom Plantae Class Lycopodiopsida Family Lycopodiaceae Rank Species | Division Lycopodiophyta Order Lycopodiales Genus Lycopodium | |
 | ||
Similar Lycopodium lagopus, Lycopodium dendroideum, Lycopodium obscurum, Dendrolycopodium, Diphasiastrum digitatum | ||
Lycopodium hickeyi, Hickey's tree club-moss or Pennsylvania clubmoss, is North American a species of clubmoss in the family Lycopodiaceae. It is native to eastern and Central Canada (from Newfoundland to Ontario with isolated populations in Saskatchewan) and the eastern and north-central United States (from Maine west to Minnesota and south as far as Tennessee and North Carolina).
Lycopodium hickeyi is very similar to L. obscurum except for a few minor but consistent features: side shoots round rather than flat in cross section, leaves all the same size.
The oldest for the taxon is Lycopodium obscurum var. isophyllum. In elevating the plants from varietal level to species level, Wagner et al. opted to forgo the common (but not mandatory) custom of using the old varietal epithet as the new species epithet. They chose instead the name Lycopodium hickeyi while acknowledging the old varietal name as synonym.