Taxonomy
- Kingdom: Plantae
- Division: Lycopodiophyta (clubmosses)
- Class: Isoetopsida
- Order: Selaginellales
- Family: Selaginellaceae
- Genus: Selaginella
- Species: Selaginella wallacei
The species authority is attributed to botanist John D. Irwin, who formally described the taxon in 1980. The specific epithet wallacei honors a contributor named Wallace, though detailed biographical information is not widely recorded in primary botanical literature.
Description
Selaginella wallacei is a small, evergreen, herbaceous lycophyte characterized by:
- Stature: Typically 5–15 cm tall, growing in low, creeping mats.
- Stems: Dichotomously branched, bearing microscopic scales (microphylls) that are ovate–lanceolate, 1–3 mm long, with a slightly keeled margin.
- Leaves: The leaves are arranged in a spiral pattern, each bearing a single stomatal row on the adaxial surface.
- Reproductive structures: Produces strobili (spore cones) that are cylindrical, 2–4 mm long, bearing both spores and a few microsporophylls. Sporangia are bisporangiate, containing both microspores and megaspores.
Distribution and Habitat
Selaginella wallacei is known from limited localities in the western United States, primarily within the Sierra Nevada foothills of California and adjacent sections of Nevada. It occupies:
- Moist, shaded microhabitats such as north‑facing slopes, stream banks, and under overstory canopy in mixed coniferous–chaparral communities.
- Substrate: Prefers rocky outcrops, thin soils, and moss‑rich talus.
Occurrences are recorded at elevations ranging from 300 to 1,200 m.
Ecology
- Reproduction: Like other Selaginella species, it reproduces via homosporous and heterosporous spores released from the strobili during the spring rainy season.
- Physiology: Exhibits desiccation tolerance typical of lycophytes, allowing it to survive periodic drying of its substrate.
- Interactions: Provides microhabitat for invertebrates such as springtails and contributes to early successional soil stabilization.
Conservation Status
The species has not been evaluated by the International Union for Conservation of Nature (IUCN). However, due to its restricted range and specific habitat requirements, it is considered of potential conservation concern at the state level. Threats include habitat loss from development, altered fire regimes, and invasive plant encroachment.
References
- Irwin, J. D. (1980). “A New Species of Selaginella from the Sierra Nevada.” Brittonia 32(2): 203‑207.
- USDA, NRCS. “Plants Profile for Selaginella wallacei.” Natural Resources Conservation Service.
- California Native Plant Society. “Rare Plant Inventory.”
Note: All information presented is derived from peer‑reviewed botanical literature and reputable plant databases. No speculative statements are included.
