- = Calamistrum L. ex Kuntze, Revis. Gen. Pl. 2, 822 (1891) nom. illeg.
Aquatic ferns, or ferns of periodically wet places. Rhizomes short- to long-creeping, branching, bearing roots at nodes, bearing septate hairs or almost glabrous (not NZ). Leaves monomorphic, not articulated to rhizome, arising at nodes, with long stalks lacking lamina segments, herbaceous, glabrous. Veins greatly reduced, undivided. Sporocarps globose, sessile or stalked, hardened, hairy, attached to the rhizome at the base of the leaf stalks, opening with two valves, each containing at least two sori. Each sorus containing both mega- and microsporangia. Megaspores spheroidal to slightly ellipsoidal, plain to slightly undulate; microspores spheroidal, and plain, papillate or rugulate.
A genus of 6 species (Nagalingum et al. 2008) in temperate regions; one species in North and South America, two in Europe, one in Australia and New Zealand, and two in southern Africa (Crouch et al. 2011). One species in New Zealand; none endemic.
Category | Number |
---|---|
Indigenous (Non-endemic) | 1 |
Total | 1 |
The base chromosome number in Pilularia is x = 10 (Smith et al. 2006).
Based on analysis of five different genes, Nagalingum et al. (2008) showed that Pilularia comprises two highly supported groups – P. minuta and P. globulifera from Europe, and P. americana and P. novae-hollandiae from North America, Australia and New Zealand. The two subsequently described African species (Crouch et al. 2011) were not included in the phylogeny.