Selaginella arizonica Maxon

  • 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 arizonica Maxon

  • Description

    Species Description - Stems prostrate, forming rather loose mats, not readily fragmenting, dorsiventral, tips upturned in extremely dry conditions, 6-15 cm long, 0.5-0.7 mm diam., not articulate, not flagelliform, not stoloniferous, irregularly branched, branches determinate, 2-3 times branched; rhizophores borne throughout stem length, 0.2-0.3 mm diam.; leaves of one kind (isophyllous) throughout, tightly appressed to ascending, green, apices aristate, sometimes becoming acute by breaking off of aristae, aristae flattened, transparent to opaque, 0.1-0.3 mm, dentate at margins; upperside leaves linear-lanceolate, slightly falcate, 1.3-2.3 x 0.4- 0.6 mm, bases abruptly adnate, pubescent or glabrous, margins green, ciliate, the cilia hyaline to opaque, spreading; underside leaves lanceolate, falcate, 2-2.5 x 0.5-0.6 mm, bases decurrent, glabrous, margins ciliate, the cilia hyaline to opaque, spreading or ascending; strobili quadrangular, 5-10 mm long; sporophylls monomorphic; megasporangia in two ventral rows; microsporangia in two dorsal rows; megaspores yellow, rugose to reticulate, 320-340 µm diam.; microspores orange.

  • Discussion

    Bryodesma arizonica (Maxon) Soja´k, Preslia 64: 154. 1992. Type. U.S.A. Arizona: Foot of Soldier Trail, Santa Catalina Mountains, Shreve s.n. (US!; isotypes GH, MO!, NY!).

    Selaginella arizonica can be distinguished from the similar S. peruviana by its underside leaves broad and thin, versus narrow and fleshy in S. peruviana.

  • Distribution

    Terrestrial or epipetric, in rock crevices or on gravel, on sandstone, igneous, or rarely limestone substrates; 500-2200 m. USA; Mexico.

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