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

652 DIOSCOREACEAE
known collection of the species in TX—all other East TX specimens (e.g., Anderson, Henderson,
Jasper, Polk, and Tyler county sheets at BRIT) of this complex we have seen have pubescent
fruits and thus fall into S. muehlenbergii; Reznicek (pers. comm.) noted that S. reticularis is “undoubtedly
rare and disjunct in Texas”; no county distribution map is provided; e U.S. w to WI
and MS, disjunct to TX. Summer–fall. According to Reznicek et al. (2002), S. reticularis “is a
smaller plant and less widely distributed than S. muehlenbergii. …” and “differs from S.
muehlenbergii in having the lobe[s] of the hypogynium obtuse and emarginate at the apex
rather than obtuse to acute, the terminal internode of the stem usually 3–8 cm rather than 6–30
cm, and scales of pistillate flowers mostly 3–4 mm rather than 4–5 mm.” There are nomenclatural
problems with S. reticularis, and a proposal (Camelbeke et al. 2003) has been made to
conserve the name with a new, conserved type. By using S. reticularis, we are following the recommendations
of this proposal. While not officially designated as such (e.g., TOES 1993; Carr
2002d; Poole et al. 2002), given its limited distribution in the state, we consider this species to be
of conservation concern in TX. �
Scleria triglomerata Michx., (three-clustered), WHIP-GRASS, WHIP NUT-RUSH, TALL NUT-RUSH, TALL
NUT-GRASS. Rhizomatous perennial (20–)40–100 cm tall; inflorescence of 1–3 head-like masses
of spikelets; achene body 1.5–3.5 mm long, smooth; basal pad completely covered with rough
whitish crust, without distinct tubercles. Sandy open woods, savannahs, low areas, moist to dry
sites; Pineywoods and Gulf Prairies and Marshes w to East Cross Timbers; se Canada and widespread
in e 1/2 of the U.S. Jun. [S. flaccida Steud., S. minor (Britton) W. Stone, S. nitida Willd., S.
triglomerata var. minor Britton] The fruits are reportedly dispersed by ants, with the basal pad
(= hypogynium) acting as an elaiosome (= appendage used in dispersal by ants or other insects)
(Gaddy 1986; Tucker 1987). While we are tentatively treating this species broadly (as do Jones et
al. 1997), some authorities believe the variation present warrants recognition of the segregate S.
minor; at this point we have seen no TX material that supports such separation. The Newton
Co. collection (Correll, Johnson, & Edwin 22269, duplicate at BRIT) cited by Core (1966) as S.
minor has leaves to ca. 5 mm wide and achenes more than 2 mm long. Core also noted that S.
minor is “perhaps only a reduced state of S. triglomerata.” Reznicek et al. (2002) cited both S.
triglomerata and S. minor for TX, distinguishing the two as follows:
1. Leaves 3–9 mm wide; achenes 2–3 mm [long] ________________________________________ S. triglomerata
1. Leaves 1–2.5 mm wide; achenes 1.5–2 mm [long] __________________________________________ S. minor
Scleria verticillata Muhl. ex Willd., (whorled), LOW NUT-RUSH, WHORLED NUT-RUSH, LOW NUT-
GRASS, WHORLED NUT-GRASS. Slender, tufted, often inconspicuous annual from fibrous aromatic
roots, 10–60 cm tall; inflorescence spike-like and interrupted, with (2–)3–7(–9) distinct, wellspaced
clusters of spikelets in addition to the terminal cluster; achene body not subtended by a
basal pad, usually 1–1.5 mm long, warty to wrinkled or horizontally ridged., Savannahs,
pinelands, stream banks, seeps, sometimes in shallow water, wet sand, sandy peat, or marl soils,
and wet areas on rocks; collected in Dallas Co. by Reverchon (Core 1966), also Liberty (Bridges
& Orzell 1989a), Guadalupe, Hays, Limestone, Travis (Turner et al. 2003), and Polk (J. Singhurst,
pers. comm.) cos.; also Cross Timbers and Prairies (Wise Co.—BRIT, TAMU) and e Edwards Plateau
(e.g., at margin of temporary pool on granite outcrop, Llano Co., Walters 937, BRIT); se
Canada and widespread in e 1/2 of the U.S. Jul–Sep. [S. tenella Kunth] This species is somewhat
similar to S. distans but can be distinguished by its rough achenes and glabrous spikelet scales
versus smooth achenes and spikelet scales with conspicuous � straight hairs in S. distans.
DIOSCOREACEAE R. Br. YAM FAMILY
AA medium-sized family of ca. 650 species in 7 genera (Raz 2002), with the number of genera
recognized by various authorities ranging from 3–20 (Raz 2002). Some authorities (e.g.,