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

446 AMARYLLIDACEAE/COOPERIA
AA small American genus of ca. 6–7 species (Correll & Johnston 1970) sometimes recognized as
a subgenus of Zephyranthes (Traub 1963a) and recently submerged into that genus by some authors
(e.g., Mabberley 1997; Meerow & Snijman 1998; Meerow et al. 2000b; Ward 2000; Flagg et al.
2002b). Cooperia can be distinguished by its fasciculate stamens and elongate perianth tube. Hybrids
with Zephyranthes are known (Flagg & Flory 1976; Flagg et al. 2002b). However, molecular
evidence (Meerow et al. 1999 [2000], 2000b) indicated that Zephyranthes is polyphyletic, with
possibly three origins. Given this and the uncertainty of the future generic placement of Cooperia
species, we are following Correll and Johnston (1970), Kartesz (1994, 1999) and Jones et al. (1997) in
maintaining Cooperia as a distinct genus pending further study and clarification of nomenclature.
� Ingestion of Cooperia is thought to be a cause of photosensitization (= increased sensitivity
to light, thus easily sunburned) observed in cattle in s TX; the specific toxin is unknown.
Symptoms include reddening, swelling, edema, and sloughing and peeling of the skin (Burrows
& Tyrl 2001). (Named for Daniel Cooper, ?1817–1842, an English botanist and gardener)
REFERENCES: Cory 1950a; Ward 2000; Flagg et al. 2002b.
1. Flower sessile, the ovary borne just above attachment of subtending bract; perianth tube (from
base to where perianth begins to widen) greatly elongate, (3.4–)6–18 cm long; style � 40 mm
long, longer than perianth tube.
2. Style typically exceeded by the anthers or nearly so; species widespread in East TX ______ C. drummondii
2. Style usually exceeding the anthers; species in East TX known only from Colorado Co. at s
margin of area ___________________________________________________________________ C. traubii
1. Flower pedicelled, the ovary borne well above attachment of subtending bract (base of ovary
usually 5–25 mm above bract attachment); perianth tube usually shorter, 2.2–4(–4.7) cm long;
style � 35 mm long, shorter than perianth tube _____________________________________ C. pedunculata
Cooperia drummondii Herb., (for its discoverer, Thomas Drummond, 1780–1835, Scottish botanist
and collector in North America), CEBOLLETA, RAIN-LILY, BRAZOS RAIN-LILY. Spring leaves 1–3(–5)
mm wide; flowers white, sometimes with pink tinge or pink veins; perianth salverform, the
limb nearly flat, ca. 1/4 as long as the long, slender, pedicel-like basal tube, the lobes 12–20 mm
long, obtuse, rarely reflexed; stamens appearing equal in length. Prairies, lawns, roadsides, often
on thin soils over limestone; widespread in TX except Panhandle; AL, AR, KS, LA, MS, OK, and
TX. Jun–Oct, typically after a rain. [Zephyranthes brazosensis (Herb.) Traub, Zephyranthes
chlorosolen (Herb.) D. Dietr., Zephyranthes herbertiana D. Dietr.] The flowers open in the late
afternoon or evening (Kirkpatrick 1992). This species possibly causes photosensitization (= increased
sensitivity to light, thus easily sunburned) in cattle (Burrows & Tyrl 2001). � m/283
Cooperia pedunculata Herb., (peduncled, stalked, or footed), GIANT RAIN-LILY, PRAIRIE RAIN-LILY,
WHITE RAIN-LILY, WIDE-LEAF RAIN-LILY, EVENING STAR RAIN-LILY. Spring leaves 4–10 mm wide;
flowers white, sometimes with pink beneath; perianth broadly funnelform, the limb about 1/2
or more as long as the narrowly cylindric basal tube, the lobes 25–30 mm long, each with an
abrupt small point, rarely reflexed; stamens subequal. Rocky or sandy soils, prairies, roadsides,
open woods; scattered in s part of East TX; scattered in s 1/2 of TX; FL, LA, and TX. Apr–Jul,
typically a few days after heavy rains. [Zephyranthes drummondii D. Don.] According to Wills
and Irwin (1961), the flowers “… open slowly around dusk or earlier on cloudy days, the lobes
gradually spreading during the night, and appearing fully expanded the next morning. Ordinarily
each flower lasts only one day, turning pale pink before withering, but in dull weather
withering may not occur until the second day.” Individuals “with rare biflowered inflorescences
were collected by B.C. Tharp in 1930 and 1946 in Austin, Texas” (Flagg et al. 2002b). Dead leaves
of this species (when wet after rains) are thought to cause photosensitization in cattle; microbiological
activity may be involved (Burrows & Tyrl 2001; Hart et al. 2001). � m/283
Cooperia traubii Hayw., (for H.P. Traub, 1890–1983, horticulturist and specialist in the
Amaryllidaceae), TRAUB’S RAIN-LILY. Similar to C. drummondii, but more delicate in appearance;
leaves only ca. 1 mm wide; flowers white, sometimes with pink tinge or pink veins; perianth