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Selaginellaceae

Selaginella ×neomexicana Maxon

Kingdom: Plantae Rank: Species Parent: Selaginella Status: Valid

Common Names:

  • NEW MEXICO SPIKE-MOSS - English, United States of America

Morphological Description

Diagnosis: Plants forming clumps, the aerial stems erect to ascending (can be pendant in large plants when on a nearly vertical surface), radially symmetrical, with rhizophores mainly on lower ½ of erect aerial stems; underground (rhizomatous) stems present; rhizomes and aerial stems often with a bud-like arrested branch near base; leaves of aerial stems essentially of 1 kind, appressed, linear-lanceolate, 1.9–2.7 mm long, marginally long-ciliate at base but merely minutely denticulate toward apex, apically keeled, with whitish bristle; strobili solitary, quadrangular, usually 1–3 cm long; sporophylls apically keeled, bristled.

Other

Ecology: On rocks of canyons, often on granite: rare in the Trans-Pecos and adjacent Val Verde Co.—in the Franklin Mts., El Paso Co. (e.g., Correll 15025, 15035, TEX-LL), and Chisos Mts. and Sunny Glen, Brewster Co. (P. Zelazny 93, SRSC; Yarborough & Powell 2002), and reported for Presidio and Val Verde cos. (Correll 1956; Yarborough & Powell 2002) (we have been unable to relocate the Val Verde Co. collections cited by Correll; therefore the location for that county is mapped in the sw part of Val Verde w of the Pecos River since Correll described the species as being “rare in the Trans-Pecos region of west Texas”); endemic to AZ, NM, and TX. Spores lacking or malformed.

This interspecific hybrid is of conservation concern.

Notes: This taxon, which is clearly similar in many ways to S. rupincola (e.g., long, spreading, marginal leaf cilia, rhizomatous underground stems) has long been treated as a hybrid (e.g., Tryon 1955; Velaspino 1993); megaspores and megasporangia are lacking and the microsporangia are misshapen. It has been proposed that possible parents are S. rupincola and S. mutica (Tryon 1955) (like S. ×neomexicana, the sympatric S. mutica has strongly keeled leaf apices). Velaspino (1993) suggested S. rupincola × S. underwoodii (also sympatric) as another possible parentage or even that ×neomexicana is an asexual race of S. rupincola. Further research is clearly needed to clarify its relationships. Given its very limited range (endemic to extreme s AZ, NM, and TX) and rareness, we consider this taxon to be of conservation concern. (of New Mexico, the species occurring in NM as well as AZ and TX)