Lycopodiella prostrata

Lycopodiella prostrata (R.M. Harper) Cranfill
(Latin: prostratus, down flat, laid low, prostrate, in reference to the prostrate stems)

Local names: feather-stem bog club-moss, creeping club-moss, prostrate bog club-moss, southern clubmoss, feather-stem club-moss

Horizontal stems long-creeping, flat on ground, essentially rooting throughout, 1–1.5 mm in diam. (excluding leaves); leaves linear-lanceolate, 3–8 mm long, 0.4–1.8 mm wide, with conspicuous marginal teeth, spreading, nearly perpendicular to stem, slightly dimorphic, those of the upper side slightly smaller (3–5 mm long); upright stems usually unbranched, 15–35 cm tall, densely covered with leaves; strobili 4–8 cm long, 15–20 mm wide; sporophylls wide-spreading; 2n = 156 (Wagner & Beitel 1993). Travis Co. (Correll 1956—“B.C. Tharp s.n.”; Turner et al. 2003) near the w edge of the Blackland Prairie, also the range map in Wagner and Beitel (1993) indicates occurrence in the extreme se part of the Pineywoods and the n part of the Gulf Prairies and Marshes as well as c TX (while we have followed Wagner and Beitel in mapping this species along the TX Gulf coast on our U.S. map, we have been unable to find supporting specimens); se U.S. from NC s to FL w to AR and TX. Sporulating mainly summer–fall. [Lycopodium alopecuroides L. var. pinnatum (Chapm.) J. Lloyd & Underw. ex C.A. Br. & Correll, Lycopodium inundatum L. var. pinnatum Chapm., Lycopodium prostratum R.M. Harper] Correll (1956), who treated this taxon as L. alopecuroides var. pinnatum, indicated that it was known in TX only from Travis Co., but did not cite the herbarium of the B.C. Tharp s.n. collection (dates and herbaria of specimens were not included in Correll’s book as part of the listings of specimens). We have not been able to relocate that collection. Carr (2002d) noted, “It is possible that a Tharp specimen at TEX-LL [of L. appressa], collected 15 Oct 1939 from Austin County, was mistakenly attributed to the city of Austin and thus to Travis County. Lycopodiella prostrata occurs mainly in mesic to wet pine forests of the southeastern United States, and its presence in Travis County seems unlikely.” However, Correll (1956) noted that “The apparent isolation of this variety on the western edge of the Blackland Prairies, far from its nearest known stations to the east in Beauregard and Natchitoches parishes, Louisiana, is of uncommon interest.” It thus seems unlikely that Correll would not have carefully studied the specimen. (A similar situation involving Cheilanthes lanosa was recently resolved with Correll’s sole citation for TX being confirmed [Holmes et al. 2011]). Therefore, until further information is available, we are accepting Correll’s citation and including L. prostrata in the TX flora. Also, although the Travis Co. site is significantly disjunct to the w from most of the range of the species, such a disjunction is not uncommon in homosporous pteridophytes (see pages 2, 30). This species hybridizes with L. alopecuroides (Snyder & Bruce 1986) and has sometimes been lumped with it (Radford et al. 1968); however, most recent taxonomic treatments (e.g., Wagner & Beitel 1993; Nauman et al. 2000) recognize both species. It also hybridizes with L. appressa (to form L. ×brucei Cranfill); two specimens at TEX-LL appear to be examples of such a hybrid (Jasper Co., Correll & Correll 12518; Jefferson Co., Mrs. J.L. Hooks s.n. , “1/51936”). Because of its rareness and limited distribution in the state, we consider this species to be of conservation concern in TX.

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