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Edwards Plateau greenthread, slender greenthread

burridge's greenthread

Habit Perennials or subshrubs (may flower first year), (20–)30–70+ cm. Annuals, 30–40(–70+) cm.
Cauline leaves

± scattered over proximal 3/4+ of plant heights, internodes mostly 45–95 mm;

lobes mostly linear to filiform, sometimes oblanceolate, (5–)15–45(–60) × 0.5–1(–2) mm.

crowded to ± scattered over proximal 1/2–3/4 of plant heights, internodes mostly 5–40(–60+) mm;

lobes mostly linear to filiform, sometimes oblanceolate, 5–25(–45) × 0.5–1(–2+) mm.

Ray florets

usually 8, rarely 0;

laminae yellow, 9–15(–20+) mm.

8;

laminae wholly red-brown to purplish or mostly red-brown with distal margins yellow to orange, 7–9(–12+) mm.

Disc corollas

yellow with red-brown nerves, throats equal to or longer than lobes.

red-brown to purplish, throats shorter than lobes.

Calyculi

of 6–8+ linear to subulate bractlets 1–3+ mm.

of 5–6(–9) linear to narrowly triangular bractlets 2–4 mm (margins hispido-ciliate).

Cypselae

3–4 mm;

pappi usually 0, rarely 0.1–0.3+ mm.

3.5–4 mm;

pappi 0.5–1+ mm.

2n

= 20.

= 18.

Thelesperma simplicifolium

Thelesperma burridgeanum

Phenology Flowering Apr–Jul(–Oct). Flowering Apr–Jun.
Habitat Openings in oak/juniper woodlands or desert scrub, usually on limestone Disturbed sites on sands
Elevation 100–1500 m (300–4900 ft) 10–200 m (0–700 ft)
Distribution
from FNA
TX; Mexico (Chihuahua, Coahuila, Nuevo León, Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
from FNA
TX
[BONAP county map]
Discussion

Thelesperma simplicifolium is used in roadside plantings and may be encountered as a waif outside its natural range in the flora area (e.g., in California).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Thelesperma burridgeanum may be a color-form of T. filifolium.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 21, p. 201. FNA vol. 21, p. 202.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Coreopsidinae > Thelesperma Asteraceae > tribe Heliantheae > subtribe Coreopsidinae > Thelesperma
Sibling taxa
T. ambiguum, T. burridgeanum, T. filifolium, T. flavodiscum, T. longipes, T. megapotamicum, T. nuecense, T. subnudum
T. ambiguum, T. filifolium, T. flavodiscum, T. longipes, T. megapotamicum, T. nuecense, T. simplicifolium, T. subnudum
Synonyms Cosmidium simplicifolium, T. curvicarpum Cosmidium burridgeanum
Name authority (A. Gray) A. Gray: Hooker’s J. Bot. Kew Gard. Misc. 1: 252. (1849) (Regel) S. F. Blake: Proc. Biol. Soc. Wash. 41: 146. (1928)
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