The Lycopodiales are an ancestral group of living and extinct clubmosses which are all herbaceous. Unlike more derived lycophytes, they are homosporous, producing only one kind of spore, and lack specialized spore-cones. Living species are mainly tropical, but several occur in temperate, arctic and subalpine regions. All are trailing plants from a rhizome. In some species, variations and gradations between dichotomous and pseudomonopodial growth patterns occur.
Above: Huperzia lucidula, the shining clubmoss, found in eastern North America
Stems
Morphology: Dichotomous branching is isotomous or anistomous in nature
Anatomy: Vascular tissue is arranged as a protostele, frequently a plectostele
Leaves
Possess leaves, called microphylls or lycophylls, which are small in nature
Leaves are arranged helically around the stem, giving them a moss-like appearance
Sporangia
Most have sporangia that are aggregated into cones, which have a club-like appearance
Some, like Huperzia, have sporangia that are diffuse along stem
All members of Lycopodiales are homosporous
Sporangia are located on the adaxial surface of special leaves, which are called sporophylls
Small, but multicellular gametophytes
Photosynthetic
Above: Gametophytes of Lycopodiella
Above: Sporophyte emerging from a Lycopodium gametophyte
Late Devonian - present
1 extant family (Lycopodiaceae)
3 extant subfamilies (see below)
16 extant genera (see below)
400 extant species
Lateristachys
Lycopodiella
Palhinhaea
Pseudolycopodiella
Austrolycopodium
Dendrolycopodium
Diphasiastrum
Diphasium
Lycopodiastrum
Lycopodium
Pseudodiphasium
Pseudolycopodium
Spinulum
Huperzia
Phlegmariurus
Phylloglossum
Above: Palhinhaea cernua
Above: Dendrolycopodium dendroideum
Above: Pseudodiphasium volubile
Above: Pseudolycopodiella caroliniana
Above: Spinulum annotinum
Above: Phylloglossum drummondii
Clubmosses in a Catskill forest (YouTube 2020)
Pygmy clubmosses: Phylloglossum (In Defense of Plants, Nov 2018)