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

782 ORCHIDACEAE/SPIRANTHES
20. Leaves often extending well up the stem and sometimes merging
gradually with the bracts below the inflorescence, present at flowering
time; petioles more than 7 mm wide; flowers strongly fragrant; lip
(when flattened) not constricted or only slightly so, � tapering from
wider base to apex; often in swamps or wet forested sites primarily in
the Pineywoods _____________________________________________ S. odorata
Spiranthes brevilabris Lindl., (short-lipped), TEXAS LADIES’-TRESSES. Plant (including inflorescence
and flowers) densely pubescent with capitate hairs, 7–40 cm tall; leaves 3–5, basal, usually
present at flowering time, withering after flowering, ovate, 2–6 cm long, 1–2 cm wide; spike
with flowers loosely spiraled, single-ranked, frequently 1-sided; perianth ca. 5 mm long, creamy
white to yellowish white; lip with yellow center sometimes marked with green, recurved, finely
lacerate at apex, the upper surface with a tuft or patch of hairs. Meadows and pinelands; Cass
and Tyler (Liggio & Liggio 1999) cos. in the Pineywoods; also Galveston and Harris (Liggio &
Liggio 1999) cos. in the Gulf Prairies and Marshes; se U.S. from AL s to FL w to TX. Feb–May.
[Spiranthes gracilis (Bigelow) L.C. Beck var. brevilabris (Lindl.) Correll] While this species and S.
floridana were treated as varieties of S. gracilis [= S. lacera var. gracilis] by Correll (e.g., 1961),
they flower earlier, have leaves persisting through flowering time, differ from S. gracilis in lip
characters, and in S. brevilabris, can be distinguished by the dense pubescence (Luer 1972). This
species has often been considered to include S. floridana as a variety (e.g., Hatch et al. 1990;
Liggio & Liggio 1999); see further discussion under S. floridana. Only a few collections of the
rare S. brevilabris have ever been made in TX (J. Liggio, pers. comm.). According to Sheviak and
Brown (2002), S. brevilabris “has dramatically declined, with only a single extant population
known in 1998–2000.” The species is thus obviously of conservation concern. � m/300
Spiranthes cernua (L.) Rich., (drooping, nodding, in reference to the somewhat nodding position
of the flowers), NODDING LADIES’-TRESSES, COMMON LADIES’-TRESSES, LADIES’-TRESSES, WHITE NOD-
DING LADIES’-TRESSES. Plant glabrous below, pubescent above with some capitate hairs, 10–60 cm
tall; roots fleshy, wide-spreading; leaves all basal or 1–2 near very base of stem, linear to lanceolate,
5–26 cm long and 0.5–2.5 cm wide, usually not persisting until flowering; spike pubescent, 1.5–
2 cm thick, usually with flowers multi-ranked or rarely single-ranked; flowers sometimes
scentless or only faintly fragrant; perianth white to ivory or cream, rarely pale yellowish, 6–12
mm long; lip thick, with yellow center, usually slightly to distinctly constricted near the
middle, apically recurved and undulate or crenulate; column 3–7 mm long; 2n = 45, 60 (Sheviak
1982; Sheviak & Brown 2002). Prairies, open woodlands, wetland pine savannahs, even lawns,
often on sandy soils; widespread in e 1/2 of TX; se Canada and throughout e U.S. w to MN and
TX. (Late Aug–)Oct–Nov. A form with all closed flowers is known from the Post Oak Savannah;
while the flowering spike is similar to normal S. cernua, the closed flowers are pointed in form
and are pale yellowish. These flowers, typically with the lip scarcely different from the lateral
petals, are sometimes referred to as peloric, a term used to describe various abnormal floral
morphologies and technically meaning an abnormal regularity occurring in normally irregular
flowers (Challis 2002); in these plants reproduction is vegetative through apomixis (Liggio &
Liggio 1999). As discussed by Liggio and Liggio (1999), there is considerable confusion in distinguishing
the three TX members of the S. cernua complex (S. cernua, S. odorata, S. magnicamporum).
Sheviak and Brown (2002) also noted that determination of species in this complex is
“often challenging.” This is partly due to significant morphological variability, hybridization,
morphological abnormalities, and the fact that S. cernua is a polyploid facultatively apomictic
compilospecies receiving genes from the related diploids (Sheviak 1982,1991). Using characters
(in the key above) such as presence of leaves at flowering time, floral fragrance, and habitat helps
in making definitive identifications. m/300
Spiranthes eatonii Ames ex P.M. Br., (for A.A. Eaton, 1865–1908, who collected the species during a
Florida trip for Oakes Ames), EATON’S LADIES’-TRESSES. Plant 15–55 cm tall; leaves all basal, usually