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

Navajo tea, plains greenthread, stiff greenthread

Habit Perennials or subshrubs, (20–)30–80+ cm. Annuals (sometimes persisting), 10–40(–70+) 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.

crowded to ± scattered over proximal 1/2–3/4 of plant heights, internodes mostly 10–35(–50+) mm;

lobes mostly linear to filiform, sometimes oblanceolate, 5–30(–55+) × 0.5–1(–3+) mm.

Ray florets

0.

8;

laminae yellow to golden yellow (sometimes proximally suffused with red-brown), 12–20+ mm.

Disc corollas

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

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

Calyculi

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

of 7–8+ linear to narrowly triangular bractlets (2–)4–8+ mm.

Cypselae

5–8 mm;

pappi 1–2(–3) mm.

3.5–4+ mm;

pappi 0.5–1(–2+) mm.

2n

= 22, 44.

= 16, 18.

Thelesperma megapotamicum

Thelesperma filifolium

Phenology Flowering (Apr–)May–Oct. Flowering Mar–Aug(–Oct).
Habitat Disturbed places on sands or clays, oak/juniper woodlands, desert scrub, yellow-pine forests Disturbed sites on clays or sandy soils, rocky slopes, often on limestone
Elevation 300–2900 m [1000–9500 ft] 10–2200 m [0–7200 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 filifolium includes plants that others have treated as a distinct species or variety: T. intermedium or T. filifolium var. intermedium, characterized as plants mostly 10–40 cm (versus taller); internodes “relatively short” (versus longer); calyculus bractlets mostly 1/4–1/2 lengths of phyllaries (versus more than 1/2 as long); ray corollas yellow (versus “golden yellow”); disc corollas yellow (versus sometimes red-brown); distribution mostly north and west of the typical form (Colorado, Kansas, Nebraska, New Mexico, w Oklahoma, South Dakota, c and w Texas, Wyoming).

According to A. Cronquist (1980), Thelesperma trifidum (Poiret) Britton has been misapplied (e.g., M. L. Fernald 1950) to T. filifolium.

(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
AR; CO; KS; LA; MO; MS; NE; NM; OK; SD; TX; WY; Mexico (Nuevo León)
[WildflowerSearch map]
[BONAP county map]
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. nuecense, T. simplicifolium, T. subnudum
T. ambiguum, T. burridgeanum, T. flavodiscum, T. longipes, T. megapotamicum, T. nuecense, T. simplicifolium, T. subnudum
Synonyms Bidens megapotamica, T. gracile Coreopsis filifolia, T. filifolium var. intermedium, T. intermedium
Name authority (Sprengel) Kuntze: Revis. Gen. Pl. 3(2): 182. (1898) (Hooker) A. Gray: Hooker’s J. Bot. Kew Gard. Misc. 1: 252. (1849)
Source Flora of North America vol. 21, p. 202. Flora of North America vol. 21, p. 202.
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