Selaginella ribae Valdespino

  • Authority

    Mickel, John T. & Smith, Alan R. 2004. The pteridophytes of Mexico. Mem. New York Bot. Gard. 88: 1-1054.

  • Family

    Selaginellaceae

  • Scientific Name

    Selaginella ribae Valdespino

  • Description

    Species Description - 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.

  • Discussion

    Type. Mexico. Guerrero: Mpio. Zupango del Ri´o, 38 km S of Iguala, ca. 0.5 km N de Xilitla [Xalita] along the road to road Acapulco, Koch et al. 7987 (holotype NY!; isotypes CAS!, MEXU!, NY!).

    Inter species rosulares Selaginellae, S. ribae apicibus foliorum lateralium et medianorum rotundatis vel late obtusis distincta. (Dedicated to the late Ramo ´n Riba, dean of Mexican pteridology.)

    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).

  • Distribution

    Terrestrial or epipetric on rocky hillsides, rocky soil, steep slopes; 600–950 m. Mexico.

    México Mexico North America|