Lycopodiella is a genus in the clubmossfamilyLycopodiaceae. The genus members are commonly called bog clubmosses, describing their wetlandhabitat. The genus has a cosmopolitan, with centers of diversity in the tropical New World and New Guinea. In the past, the genus was often incorporated within the related genus Lycopodium, but was segregated in 1964. In the Pteridophyte Phylogeny Group classification of 2016, Lycopodiella is placed in the subfamily Lycopodielloideae, along with three other genera. In this circumscription, the genus has about 15 species. Other sources use a wider circumscription, in which the genus is equivalent to the subfamily of PPG I, in which case about 40 species and hybrids are accepted.
Description
Lycopodiella are non-flowering plants. They have leafy rhizomes that grow along the ground and vertical, leafy shoots, also known as peduncles. Fertile peduncles have strobili at the top of the shoot. Individuals can have short, creeping rhizomes with simple strobili, branching rhizomes with many strobili, or anywhere in between. The North American specimens are typically shorter, have thinner shoots, and have fewer vertical shoots in the North than specimen in the South.
Life cycle
Lycopodiellalife cycles include an independent sporophyte stage and a long-lived gametophyte stage. Individuals reproduce by single-celled spores that disperse and germinate into small plants when in suitable conditions. This part of the plant is called the gametophyte; it produces the eggs and sperm. After fertilization, the embryos grow into sporophytes, which are larger spore-bearing plants. The sporophyte is the vegetative part of the plant seen in nature. Juvenile individuals typically re-sprout in the spring or after a fire. Individuals have a base chromosome number of 78.
Taxonomy
In the Pteridophyte Phylogeny Group classification of 2016, Lycopodiella is placed in the subfamily Lycopodielloideae, along with three other genera. Other sources do not recognize these genera, submerging them into Lycopodiella.
Extant species
, the Checklist of Ferns and Lycophytes of the World recognized the following species:
Lycopodiella subappressa J.G.Bruce, W.H.Wagner & Beitel – northern appressed clubmoss; United States
Lycopodiella tupiana B.Øllg.
Some hybrids have also been described:
Lycopodiella × brucei Cranfill
Lycopodiella × copelandii Cranfill
Lycopodiella × gilmanii A.Haines
Lycopodiella × robusta A.Haines
Using the broader circumscription of the genus, Plants of the World Online recognized the following additional Lycopodiella species as of 2019. Using the narrow circumscription of the genus Lycopodiella, the Checklist of Ferns and Lycophytes of the World divided them among three other genera:
Lycopodiella is found worldwide, but typically in temperate and tropical areas, a majority of which are found in North and South America. Individuals are typically found in terrestrial lowlands or montane forests on poor soils. Much of the soils are sandy and saturated and have little to no organic layer.
The known Lycopodiella in North America consists of six species and four hybrids. All but one species of Lycopodiella, Lycopodiella inundata, are limited to the East coast, Gulf of Mexico, and/or Great Lakes region. L. inundata is found from New England to Alaska and down into California.
