keys to the vascular plants of east texas - Botanical Research ...

330 SELAGINELLACEAE/SELAGINELLA
(e.g., Valdespino 1993; Korall et al. 1999) who continue treating all species in a single genus.
Tropical species are known for their unusually colored leaves—reddish or bronze or iridescent
blue-green (Hoshizaki & Moran 2001). (From Selago, an ancient name for Lycopodium, a genus
resembling Selaginella, and the Latin diminutive suffix, -ella)
REFERENCES: Clausen 1946; Tryon 1955; Skoda 1997.
1. Plants of moist habitats, delicately thin-herbaceous; stem leaves not overlapping or only slightly
so, in 4 ranks, 2 lateral and spreading, 2 smaller and appressed-ascending along the upper surface
of the stem; under surface of the stem easily visible; plants annual ________________________ S. apoda
1. Plants of xeric habitats, rather rigid; stem leaves crowded, conspicuously overlapping, appressed
to stem, not in 4 distinct ranks; surface of the stems not visible (concealed by leaves completely
surrounding the stem); plants perennial _______________________________________________ S. arenicola
Selaginella apoda (L.) Spring var. apoda, (footless, in reference to the prostrate habit), MEADOW
SPIKE-MOSS, BASKET SELAGINELLA. Plant prostrate-creeping or ascending, often forming mats; leaves
of 2 distinct kinds; lateral leaves ovate to ovate-elliptic, asymmetrical, ca. 1.35–2.25 mm long,
0.75–1.35 mm wide; appressed-ascending leaves smaller, to ca. 1.2(–1.6) mm long; strobili solitary
or paired, obscurely quadrangular (= 4-sided)-flattened, 0.5–2 cm long; 2–4 mm in diam.; sporophylls
apically acute to acuminate. Moist areas, low fields and woods; widespread in e TX w to
Hays (BRIT), Lamar (Carr 1994), Bexar, Comal, Ellis, and Travis (Turner et al. 2003) cos., mainly
Pineywoods and Post Oak Savannah and extreme w edge of East TX adjacent to the Edwards
Plateau; also Gulf Prairies and Marshes and e Edwards Plateau; e U.S. from ME s to FL w to IL,
OK, and TX. Sporulating May–Dec. A new variety of S. apoda, var. ludoviciana (A. Braun) B.F.
Hansen & Wunderlin (based on S. ludoviciana (A. Braun) A. Braun), was recently named from
the Gulf coastal plain (Hansen & Wunderlin 1998). This variety, which differs in minor ways
(e.g., hyaline leaf margins) from var. apoda, is known from GA, FL, AL, MS, and se LA. m/298
Selaginella arenicola Underw. subsp. riddellii (Van Eselt.) R.M. Tryon, (sp.: growing in sandy
places or sand dweller; subsp.: for J.L. Riddell, 1807–1865, botanist), RIDDELL’S SELAGINELLA,
RIDDELL’S SPIKE-MOSS. Vegetative part of plant erect to ascending, forming clumps, to ca. 12 cm
tall, usually smaller; leaves essentially of 1 kind, narrowly triangular-lanceolate to linear-lanceolate,
ca. 1.2–3 mm long, 0.4–0.5 mm wide, marginally ciliate, apically with whitish bristle;
strobili solitary, sometimes with apical vegetative growth, quadrangular, ascending, (0.5–)1–3(–
3.5) cm long and ca. 1.2 mm in diam.; sporophylls often with a bristle. Rocky areas, sandy or
gravelly soils, longleaf pine sand ridges; widespread in East TX; e 1/3 of TX w to e Edwards Plateau;
AL, AR, GA, LA, OK, and TX. Sporulating throughout the year. [S. riddellii Van Eselt.]
There has long been disagreement over the taxonomy of S. arenicola. Tryon (1955) recognized
three subspecies, while other authors (e.g., Clausen 1946; Snyder & Bruce 1986) treated the three
taxa as separate species. Valdespino (1993) recognized two species in the complex, but maintained
subsp. riddellii as a subspecies of S. arenicola. Nauman et al. (2000), did not recognize
infraspecific taxa. Until further study is done, we are following Valdespino (1993) who treated
all of the taxa occurring in North America.
Selaginella peruviana (J. Milde) Hieron., (of Peru, the species ranging to South America),
PERUVIAN SPIKE-MOSS, [S. sheldonii Maxon], occurs just w of East TX (Burnet Co.—TEX, also
Comanche Co.—Stanford 1971); Edwards Plateau and Trans-Pecos; NM, OK, and TX. It can be
distinguished from S. arenicola subsp. riddellii as follows:
1. Vegetative part of plant erect to ascending; leaves not curving upward, the leaf-covered stems
therefore appearing radially symmetrical _______________________________________________ S. arenicola
1. Vegetative part of plant � prostrate; leaves curving upward making the views of the leafcovered
stems from above and below distinctly different _________________________________ S. peruviana