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green threads, Hopi tea, Hopi tea greenthread, rayless greenthread

hairy greenthread, Navajo tea

Colorado greenthread

Habit Perennials or subshrubs, (20–)30–80+ cm. Perennials, 10–30(–40+) cm (caudices often woody). Perennials or subshrubs, 10–30(–50) cm.
Cauline leaves

± scattered over proximal 1/2–3/4 of plant heights, internodes mostly 40–100 mm;

lobes mostly linear to filiform, sometimes oblanceolate, 20–40(–50+) × 0.5–1(–2.5) mm.

mostly crowded over proximal 1/4(–1/2) of plant heights, internodes mostly 1–5(–35 mm);

lobes mostly oblanceolate to linear, (5–)10–35(–45+) × (1–)2–3(–5) mm.

crowded to ± scattered over proximal 1/3–1/2 of plant heights, internodes mostly 5–50(–80+) mm;

lobes mostly linear to filiform, sometimes oblanceolate, (5–)15–75 × 0.5–1(–2) mm.

Ray florets

0.

0, or 8;

laminae yellow, (6–)12–20+ mm.

usually 8, rarely 0;

laminae yellow, 4–8(–12+) mm.

Disc corollas

yellow, often with red-brown nerves, throats shorter than lobes.

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

red-brown, throats shorter than lobes.

Calyculi

of 3–5+ ovate to oblong bractlets 1–2(–3) mm.

of 7–9 deltate to lance-linear bractlets 2–4+ mm.

of 3–5+ ovate to oblong bractlets 1–3 mm.

Cypselae

5–8 mm;

pappi 1–2(–3) mm.

5–7 mm;

pappi usually 0, rarely 0.1–0.5 mm.

4–5+ mm;

pappi usually 1.5–2+ mm, rarely 0.

2n

= 22, 44.

= 22, 24.

= 44.

Thelesperma megapotamicum

Thelesperma subnudum

Thelesperma ambiguum

Phenology Flowering (Apr–)May–Oct. Flowering May–Sep. Flowering Mar–Jun.
Habitat Disturbed places on sands or clays, oak/juniper woodlands, desert scrub, yellow-pine forests Openings in pinyon/juniper or yellow-pine forests, often on talus or "balds" Disturbed sites on sands or clays
Elevation 300–2900 m [1000–9500 ft] 1000–2900 m [3300–9500 ft] 10–200 m [0–700 ft]
Discussion

Thelesperma megapotamicum sometimes persists after plantings outside its natural range in the flora area and may become established (e.g., in California).

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

As here circumscribed, Thelesperma subnudum includes plants that have been treated as distinct species and/or varieties (some of which have been treated as of conservation concern). See C. J. Hansen et al. (2002) for an alternate interpretation of T. subnudum.

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

Thelesperma ambiguum is similar to T. megapotamicum; it may be better treated as a variety of the latter.

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

Distribution
from FNA
AR; AZ; CO; KS; NE; NM; OK; SD; TX; UT; WY; South America; Mexico (Chihuahua, Coahuila)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CO; MT; ND; NM; NV; UT; WY; AB
[WildflowerSearch map]
[BONAP county map]
from FNA
NM; TX; Mexico (Nuevo León, Tamaulipas)
[BONAP county map]
Parent taxa Asteraceae > tribe Heliantheae > subtribe Coreopsidinae > Thelesperma 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. nuecense, T. simplicifolium, T. subnudum
T. ambiguum, T. burridgeanum, T. filifolium, T. flavodiscum, T. longipes, T. megapotamicum, T. nuecense, T. simplicifolium
T. burridgeanum, T. filifolium, T. flavodiscum, T. longipes, T. megapotamicum, T. nuecense, T. simplicifolium, T. subnudum
Synonyms Bidens megapotamica, T. gracile T. caespitosum, T. marginatum, T. pubescens, T. pubescens var. caespitosum, T. subnudum var. alpinum, T. subnudum var. marginatum, T. subnudum var. pubescens, T. windhamii T. fraternum, T. megapotamicum var. ambiguum
Name authority (Sprengel) Kuntze: Revis. Gen. Pl. 3(2): 182. (1898) A. Gray: Proc. Amer. Acad. Arts 10: 72. (1874) A. Gray: Proc. Amer. Acad. Arts 19: 16. (1883)
Source Flora of North America vol. 21, p. 202. Flora of North America vol. 21, p. 201. Flora of North America vol. 21, p. 201.
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