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

416 AGAVACEAE/YUCCA
white to yellowish, and from having inflorescences branched to sparsely branched or unbranched.
In general, the plants are from 1–1.5 m tall.
T Yucca cernua Keith, (drooping or nodding, in reference to the inflorescence branches), WEEP-
ING YUCCA. Plant acaulescent, forming large solitary clumps, 1.5–4 m tall to tip of inflorescence;
rhizomes 1–2 cm wide; most leaves flat, except lowermost (these usually undulate and twisted),
the young leaves glaucous, becoming olive or yellowish green with age; mature leaves (30–)40–
70(–80) cm long, (3–)3.5–6.5 cm wide at widest point, the margins corneous (= horn-like texture);
perianth 3.4–5(–5.8) cm long, campanulate; fruits 3.2–4.5 cm long, with beaks 0.5–1 cm
long. Open or slightly shaded areas, in brownish, acidic, clayey soils of the Redco Soil Series, apparently
tolerant of soil disturbance (Keith 2003); known only from Jasper and Newton (BRIT,
Keith 2003) cos. in the e Pineywoods; endemic to East TX. May–Jun. This species was discovered
in May 2001 and described in 2003 (Keith 2003); it is the most recently described new species
in the East TX flora. In series Rupicolae, it is apparently most closely related to Y. pallida and Y.
rupicola, but it is quite distinct morphologically and disjunct geographically (� 300 km) from
those species (Keith 2003). According to Keith (2003), the tendency of the inflorescence
branches to recurve and droop is “an apparently distinctive feature separating it from all other
Yucca species.” While not officially designated as being of conservation concern (because of the
recentness of its discovery), we consider this species to be so. It is currenty known from only 7
populations (Keith 2003; E. Keith, pers. comm.). The discovery of such a distinctive new species
in the Pineywoods of East TX emphasizes the need for additional collecting and habitat conservation
in that area. � E m/307
Yucca constricta Buckley, (constricted), BUCKLEY’S YUCCA. Usually stemless, rarely with trunklike
stems to 40 cm tall; overall aspect of basal leafy portion almost ball-like in outline; leaves
100–200 per rosette, 30–65 cm long, very slender (15 mm or less wide), very straight but flexible,
the margins white or green with fibers that soon erode away; perianth pale greenish white;
panicle branches glabrous. Limestone outcrops or rocky prairies; Limestone (BRIT), Bexar,
Gonzales, Travis (McKelvey 1947), and Williamson (Turner et al. 2003) cos.; mainly Edwards
Plateau and s Lampasas Cut Plain, scattered to the s; endemic to TX (Kartesz 1999) or nearly so
(recently reported for ne Mexico—Hess & Robbins 2002). Apr–Jun. McKelvey (1947) included
both Y. louisianensis and Y. tenuistyla in this species. According to Hess and Robbins (2002),
“The major differences among these entities involve vestiture in the inflorescences.” E? m/307
Yucca gloriosa L. var. recurvifolia (Salisb.) Engelm., (sp.: glorious; var.: with recurved leaves),
CURVE-LEAF YUCCA, PENDULOUS YUCCA, WEEPING YUCCA. Plant to 2 m tall; stems unbranched or
branched; leaves 50–100 cm long, 3.5–5 cm wide, mostly recurved, flexible, usually entire; inflorescences
paniculate; perianth white to greenish white; fruits 2.5–4.5 cm long, erect. Sandy soils;
cultivated (an heirloom plant) and escaped in Hunt Co. (Matt White, pers. comm.) and persisting
around old homesites in ne part of East TX in Delta, Fannin, Franklin, Lamar, Rains, and
Van Zandt (Matt White, pers. comm.) cos.; East TX collections were brought to our attention by
Matt White after map pages were finalized; therefore no county distribution map is provided;
native to the se U.S. from FL w to LA, escaped in TX. Spring. [Y. pendula Groenl.; Y. recurvifolia
Salisb.] According to Hess and Robbins (2002) this variety is poorly known, is in need of study,
and is possibly not distinct from var. glorisa (MOUND-LILY) which occurs in GA, NC, and SC.
Yucca louisianensis Trel., (of Louisiana), LOUISIANA YUCCA, GULF COAST YUCCA. Similar to Y.
arkansana and Y. necopina but panicle much-branched and usually pubescent (rarely glabrous);
leaves 10–30(–40) mm wide, flexible but often rather firm (often more so than in Y.
flaccida), the older ones sometimes drooping, the margins white, sometimes with curly fibers;
perianth segments greenish to white, 5 cm or less long. Sandy soils; widespread in Pineywoods
and Post Oak Savannah and an outlying population on a sandy loam terrace in the Blackland
Prairie in Hunt Co. (collected in 2003 by M. White, s.n., BRIT). Apr–May. [Y. arkansana Trel.