Selaginella ribae Valdespino
Descripción
Inter species rosulares Selaginellae, S. ribae apicibus foliorum lateralium et medianorum rotundatis vel late obtusis distincta. (Dedicated to the late Ramón Riba, dean of Mexican pteridology.)
Stems rosette-forming, green to reddish, to 18 cm long, 0.5–1 mm diam., not articulate, not flagelliform, not stoloniferous, 2–3 times branched; rhizophores restricted to stem bases, stout, 0.3–0.5 mm diam.; leaves of two kinds (anisophyllous) throughout stem length, coriaceous; lateral leaves ascending, tightly imbricate, broadly ovate to ovate-deltate, 1.3–2.2 X 1.2–1.4 mm, bases rounded to cordate, margins hyaline, densely short-ciliate, apices rounded to broadly obtuse; median leaves similar to lateral leaves, tightly imbricate, ovate-deltate to suborbicular, 1–1.7 X 1–1.7 mm, bases rounded, margins hyaline, densely short-ciliate, apices rounded to broadly obtuse; axillary leaves similar to median and lateral leaves, bases cordate, exauriculate; strobili quadrangular, 4–8 mm long; sporophylls monomorphic (ventral ones sometimes less green); megasporangia mostly basal on two ventral rows; microsporangia in two dorsal rows and on ventral rows; megaspores lemon-yellow, echinate to striate, rugose, 300–360 µm diam.; microspores orange.
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Stems rosette-forming, green to reddish, to 18 cm long, 0.5–1 mm diam., not articulate, not flagelliform, not stoloniferous, 2–3 times branched; rhizophores restricted to stem bases, stout, 0.3–0.5 mm diam.; leaves of two kinds (anisophyllous) throughout stem length, coriaceous; lateral leaves ascending, tightly imbricate, broadly ovate to ovate-deltate, 1.3–2.2 X 1.2–1.4 mm, bases rounded to cordate, margins hyaline, densely short-ciliate, apices rounded to broadly obtuse; median leaves similar to lateral leaves, tightly imbricate, ovate-deltate to suborbicular, 1–1.7 X 1–1.7 mm, bases rounded, margins hyaline, densely short-ciliate, apices rounded to broadly obtuse; axillary leaves similar to median and lateral leaves, bases cordate, exauriculate; strobili quadrangular, 4–8 mm long; sporophylls monomorphic (ventral ones sometimes less green); megasporangia mostly basal on two ventral rows; microsporangia in two dorsal rows and on ventral rows; megaspores lemon-yellow, echinate to striate, rugose, 300–360 µm diam.; microspores orange.
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Forma de vida
Epipétrica, TerrestreA
Ejemplar revisado
Dgo (Torke et al. 154, NY). Gro (Lorea 737, ENCB, MEXU; Thomas et al. 2865, NY). NL (Hinton 19975, MEXU).A
Distribución
México (país) EndémicoA
Elevación
600 – 950 mA
Ecología y Hábitat
On rocky hillsides, rocky soil, steep slopes.A
Categoría IUCN
No incluidaB
Categoría NOM-059-SEMARNAT-2010
No incluidaC
Discusión taxonómica
Selaginella ribae is a member of the S. lepidophylla group and closely resembles S. lepidophylla and S. novoleonensis in its rosette habit. It can be separated from these by its round to broadly obtuse leaves. All three species have pubescent stems, which are more visible when the median leaves are lifted or removed.
According to the information on the type, S. ribae grows on clay soils and forms dense rosettes mixed with Koch et al. 7989, the type of S. nothohybrida. Selaginella ribae can be easily distinguished from S. nothohybrida by its distally rounded lateral and median leaves (vs. long-cuspidate to aristate). In addition, S. Ribae has the proximal face of the megaspores echinate (vs. reticulate-rugose).
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According to the information on the type, S. ribae grows on clay soils and forms dense rosettes mixed with Koch et al. 7989, the type of S. nothohybrida. Selaginella ribae can be easily distinguished from S. nothohybrida by its distally rounded lateral and median leaves (vs. long-cuspidate to aristate). In addition, S. Ribae has the proximal face of the megaspores echinate (vs. reticulate-rugose).
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