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

greenthread

Habit Perennials or subshrubs, (20–)30–80+ cm. Annuals, perennials, or subshrubs, 10–70+ cm.
Stems

usually 1, erect, branched distally or ± throughout.

Leaves

mostly basal, basal and cauline, or mostly cauline; mostly opposite (distal rarely alternate);

blades usually 1(–3)-pinnately lobed (ultimate lobes oblanceolate to filiform), faces usually glabrous, rarely hairy.

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.

Involucres

hemispheric to urceolate, 4–15+ mm diam.

Receptacles

flat to convex, paleate;

paleae falling, (whitish with red-brown striae, each ± appressed to abaxial face of subtended cypsela), obovate to oblong, scarious.

Ray florets

0.

0 or ca. 8, neuter;

corollas yellow or red-brown, or bicolored (yellow and red-brown).

Disc florets/Disc corollas

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

20–100+, bisexual, fertile;

corollas yellow (with red-brown nerves) or red-brown, either with throats equal to or longer than 5, ± deltate, ± equal lobes, or with throats shorter than 5, ± lance-linear, ± unequal lobes (in either form, the abaxial sinus usually ± deeper than others).

Phyllaries

5–8 in ± 2 series, persistent, connate 1/5–7/8+ their lengths, lance-ovate to ovate, ± equal, ± leathery to membranous, margins (of distinct apices) scarious.

Calyculi

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

of 3–8+ distinct, usually spreading or reflexed, usually linear to subulate, herbaceous bractlets.

Heads

radiate or discoid, borne singly or in loose, corymbiform arrays.

Cypselae

5–8 mm;

pappi 1–2(–3) mm.

(dark red-brown or stramineous) outer often arcuate, shorter, inner more columnar, usually some or all ± obcompressed (each usually shed together with its subtending palea), faces smooth or papillate to tuberculate or verrucate, margins sometimes ± winged;

pappi 0, or persistent, of 2 retrorsely ciliate, subulate scales or awns.

x

= 12.

2n

= 22, 44.

Thelesperma megapotamicum

Thelesperma

Phenology Flowering (Apr–)May–Oct.
Habitat Disturbed places on sands or clays, oak/juniper woodlands, desert scrub, yellow-pine forests
Elevation 300–2900 m (1000–9500 ft)
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 USDA
w North America; Mexico; South America
[BONAP county map]
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.)

Species 10+ (9 in the flora).

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

Key
1. Throats of disc corollas equal to or longer than lobes; pappi usually 0, rarely of 2 awns 0.1–0.3(–0.5) mm
→ 2
1. Throats of disc corollas shorter than lobes; pappi usually of 2 awns or scales (0.5–)1–3 mm, rarely 0
→ 4
2. Cauline leaves ± scattered over proximal 3/4+ of plant heights, internodes mostly 45–95 mm
T. simplicifolium
2. Cauline leaves ± crowded over proximal 1/4–1/2 of plant heights, internodes mostly 5–25+ mm or 1–5(–35) mm
→ 3
3. Leaf lobes mostly linear to filiform, 5–25(–45+) × 0.5(–1) mm; cypselae 2–3 mm
T. longipes
3. Leaf lobes mostly oblanceolate to linear, (5–)10–35(–45+) × (1–)2–3(–5) mm; cypselae 5–7 mm
T. subnudum
4. Perennials (sometimes flowering first year); calyculi of 3–5+, ovate to oblong bractlets 1–3 mm; ray florets 0, or 8, laminae 4–8(–12+) mm; cypselae (4–)5–8 mm
→ 5
4. Annuals (sometimes persisting); calyculi of 5–9, linear to narrowly triangular bractlets (2–)4–8+ mm; ray florets 8, laminae 10–20+ mm; cypselae 3.5–5.5+ mm
→ 6
5. Plants 10–30(–50) cm; ray florets usually 8, rarely 0; disc corollas red-brown
T. ambiguum
5. Plants (20–)30–80+ cm; ray florets 0; disc corollas yellow
T. megapotamicum
6. Ray laminae proximally to wholly red-brown to purplish, or each with a proximal red-brown spot; disc corollas red-brown to purplish
→ 7
6. Ray laminae yellow to golden (rarely proximally suffused with red-brown); disc corollas yellow or red-brown
→ 8
7. Calyculi of 5–6(–9), linear to narrowly triangular bractlets (margins hispido-ciliate); cypselae 3.5–4 mm
T. burridgeanum
7. Calyculi of 6–7+, narrowly triangular bractlets (margins not ciliate); cypselae 5–5.5+ mm
T. nuecense
8. Plants 30–70(–120+) cm; cauline leaves ± scattered over proximal 9/10 of plant heights, internodes 35–100+ mm; disc corollas yellow, often with brown nerves
T. flavodiscum
8. Plants 10–40(–70+) cm; cauline leaves crowded to ± scattered over proximal 1/2–3/4+ of plant heights, internodes mostly 10–35(–50+ mm); disc corollas red-brown or yellow with red-brown nerves
T. filifolium
Source FNA vol. 21, p. 202. FNA vol. 21, p. 199. Author: John L. Strother.
Parent taxa Asteraceae > tribe Heliantheae > subtribe Coreopsidinae > Thelesperma Asteraceae > tribe Heliantheae > subtribe Coreopsidinae
Sibling taxa
T. ambiguum, T. burridgeanum, T. filifolium, T. flavodiscum, T. longipes, T. nuecense, T. simplicifolium, T. subnudum
Subordinate taxa
T. ambiguum, T. burridgeanum, T. filifolium, T. flavodiscum, T. longipes, T. megapotamicum, T. nuecense, T. simplicifolium, T. subnudum
Synonyms Bidens megapotamica, T. gracile
Name authority (Sprengel) Kuntze: Revis. Gen. Pl. 3(2): 182. (1898) Lessing: Linnaea 6: 511. (1831)
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