Selaginella tenella (P.Beauv.) Spring
Descripción
Stems ascending, suberect, or erect, stramineous, 3–15 cm long, 0.4–1 mm diam., not articulate, the stem apices infrequently flagelliform, stoloniferous, 2–3 times branched, branches frequently flagelliform; rhizophores restricted to proximal 1⁄4 or throughout stems on flagelliform plants, filiform, 0.1–0.5 mm diam.; leaves of two kinds (anisophyllous) throughout stem length; lateral leaves ovate to oblong, 1.2–3 X 0.5–2.5 mm, bases rounded to subcordate, overlapping the stems acroscopically, acroscopic margins hyaline or pale green, short-ciliate to denticulate or entire, apices acute, both surfaces glabrous, with idioblasts; median leaves distant, broadly ovate-elliptic to lanceolate, 0.7–2 X 0.4–1.4 mm, bases cuneate to subcordate or with one small auricle, margins hyaline, denticulate, apices acuminate, long-acuminate, or long-aristate, aristae 1⁄2 or more the lamina length, 0.2–0.7 mm long, upper surfaces glabrous with idioblasts; axillary leaves similar to lateral leaves, bases rounded; strobili lax and flattened, dorsiventral, 2–9 mm long; sporophylls dimorphic, the dorsal ones green, spreading, the ventral ones hyaline to pale green, ascending; megasporangia generally in two ventral rows or at the base of ventral rows, or infrequently absent; microsporangia in two dorsal rows, frequently also in the distal part of ventral side of strobili, or strobili wholly microsporangiate; megaspores white, sometimes yellowish with age, proximal faces granular to granular-reticulate, with reticulum of low ridges, distal faces reticulate with low to high ridges, 230–270 µm diam.; microspores tan to orange, echinulate to baculate, 24–31 µm diam.A
Forma de vida
Epipétrica, TerrestreA
Ejemplar revisado
Col (Orcutt 4640, BM, GH). Gro (Mexia 8725, BM, CAS, F, GH, K, MICH, MO, NY, UC, US, 8755, BM, F, GH, K, MO, NY, UC, US; Hinton 8502, MICH, NY, US, 8602, TEX). Jal (McVaugh & Koelz 1727, MICH, NY; Mexia 1276, BM, GH, MICH, MO, NY, UC, US). Nay (Castillo 6069, XAL). Sin (Mexia 2682, MO). Ver (Wendt et al. 3087, NY).A
Elevación
30 – 1000 mA
Ecología y Hábitat
On open to shady roadsides or stream banks, on sandy or clayey soil, dry or moist, mossy rocks, or rocky slopes.A
Tipo de vegetación
Selva altaA
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Selaginella tenella is defined here in a broad sense. It is characterized by having conspicuous idioblasts on the upper surface of the leaves and sporophylls. Traditionally, S. subcaulescens has been separated because of its suberect to erect stems, whereas S. tenella and S. cladorrhizans were thought to be mostly creeping or rarely ascending. Specimens of S. cladorrhizans from Belize and Guatemala, however, also have suberect and erect stems. A thorough examination of specimens of these three taxa throughout their ranges reveals no consistent character that separates them. Megaspores examined from S. tenella, S. subcaulescens, and S. cladorrhizans show only minor variations in exospore sculpturing and microstructure.
Several additional names are synonymous with S. tenella. They include S. albonitens Spring, S. mollis Fée (non A. Braun), and S. sintenisii Hieron., all of the West Indies. Two other species, S. humilis Jenman and S. maracasensis O. C. Schmidt, are probably also conspecific with S. tenella; however, we have not found type material of either of these.A
Several additional names are synonymous with S. tenella. They include S. albonitens Spring, S. mollis Fée (non A. Braun), and S. sintenisii Hieron., all of the West Indies. Two other species, S. humilis Jenman and S. maracasensis O. C. Schmidt, are probably also conspecific with S. tenella; however, we have not found type material of either of these.A