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

644 CYPERACEAE/SCIRPUS
trigonous culms. Hybrids between S. tabernaemontani and the closely related S. acutus have been
reported (Smith 1969; Dabbs 1971; Strong 1994; Smith & Yatskievych 1996).
Schoenoplectus hallii (A. Gray) S.G. Sm., (for its discoverer, Elihu Hall, 1822–1882), HALL’S BUL-
RUSH, HALL’S CLUB-RUSH. Small annual or perennial to 35(–80) cm tall, very similar to S.
saximontanus; rhizomes inconspicuous; culms cylindric, ridged when dry; 0–1 smaller bract
sometimes present in addition to the erect bract which appears like a continuation of the culm;
inflorescences with 1–5 spikelets, usually sessile or nearly so, rarely a short-stalked cluster also
present; spikelets 5–13(–20) mm long; perianth bristles absent; achenes with 15–18 prominent
(use hand lens), transverse, wavy, mostly sharp ridges, 1.3–1.7 mm long. Emergent from water
along receding water lines to terrestrial in wet areas; this species was cited by Hatch et al. (1990)
for vegetational areas 2, 3, 6, 7, and 9. However, it is not cited for TX by either Kartesz (1999),
Smith (2002b), or Turner et al. (2003), and the only TX specimens we are aware of are from recent
Wise Co. collections (O’Kennon & McLemore, 18,344, 18,853, 19,070, BRIT—identified by
S.G. Smith; O’Kennon & McLemore 2004). Smith (2002b) indicated that many reports of this
species are based on misidentified specimens of S. saximontanus. We are therefore not considering
it a member of the East TX flora; it is included here as a note for clarification. The species is
scattered mainly in the midwestern U.S. (IA, IL, IN, KS, KY, MI, MO, NE, OK, TX, and WI) but is
also known (apparently extirpated) from GA and MA (McKenzie 1998; O’Kennon & McLemore
2004). Jul–Oct. [Scirpus hallii A. Gray, Scirpus supinus L. var. hallii (A. Gray) A. Gray] Yatskievych
(1999) noted that this species is unusual and uncommon throughout its range. He also noted
that its distribution is identical to that of Echinodorus tenellus (Alismataceae); therefore, it
should be looked for where that species is found. This species shares the phenomenon of
amphicarpy with S. saximontanus (see explanation under that species). It can be distinguished
from S. saximontanus by its 2 stigmas and achenes nearly plano-convex, with one side almost
flat or slightly concave, the other side rounded. A putative hybrid between these two species
has been discovered in OK (Smith et al. 2004). While S. hallii is usually annual, in Wise Co. TX
many perennial plants have been observed; fluctuating margins of small sandy clay ponds is
the habitat of the TX populations (O’Kennon & McLemore 2004). Smith (2002c) indicated that
S. hallii is of conservation concern. (G2S1—J. Poole, pers. comm.) �
Schoenoplectus erectus (Poir.) Palla ex J. Raynal subsp. raynalii (Schuyler) Lye, SHARP-SCALE
CLUB-RUSH, which is known in TX to the s of East TX (Atascosa Co., V.L. Cory s.n., MICH; S.G.
Smith, pers. comm.), is quite similar to S. hallii. Smith (2002b) distinguished the two as follows:
1. Achenes adaxially concave or sometimes nearly plane; spikelet scale flanks pale orange to nearly
colorless ____________________________________________________________________________ S. hallii
1. Achenes adaxially longitudinally convex or horizontally slightly convex with convex center; spikelet
scale flanks often distally orange- or red-brown ________________________________________ S. erectus
SCIRPUS L. BULRUSH
Perennials of wet areas, usually with (rarely without) rhizomes; plants glabrous; culms (= stems)
obtusely triangular, with well-developed leaves; inflorescences of many spikelets in open to �
congested panicles, appearing terminal, with 2 or more well-developed leaf-like involucral
bracts; individual spikelets distinctly stalked or else sessile and in clusters; spikelets with many
florets; scales of spikelets spirally arranged, awnless or essentially so; perianth of bristles usually
present; achenes trigonous to plano-convex, without a tubercle.
AIn the strict sense, a cosmopolitan genus of ca. 35 species (Whittemore & Schuyler 2002).
Bolboschoenus, Isolepis, and Schoenoplectus have traditionally been treated as part of Scirpus
sensu lato (e.g., Mabberley 1987; Kartesz 1994). If treated in such a broad traditional sense, of
species with bisexual flowers and terete spikelets, the genus contains ca. 200–300 species
(Tucker 1987; Mabberley 1997). However, we are following Strong (1994), Smith (1995, 2002a,