Thelesperma megapotamicum |
Thelesperma |
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green threads, Hopi tea, Hopi tea greenthread, rayless greenthread |
greenthread |
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Habit | Perennials or subshrubs, (20–)30–80+ cm. | Annuals, perennials, or subshrubs, 10–70+ cm. | ||||||||||||||||||||||||||||||||
Stems | usually 1, erect, branched distally or ± throughout. |
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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. |
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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. |
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Involucres | hemispheric to urceolate, 4–15+ mm diam. |
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Receptacles | flat to convex, paleate; paleae falling, (whitish with red-brown striae, each ± appressed to abaxial face of subtended cypsela), obovate to oblong, scarious. |
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Ray florets | 0. |
0 or ca. 8, neuter; corollas yellow or red-brown, or bicolored (yellow and red-brown). |
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Disc florets/ |
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). |
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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. |
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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. |
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Heads | radiate or discoid, borne singly or in loose, corymbiform arrays. |
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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. |
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x | = 12. |
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2n | = 22, 44. |
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Thelesperma megapotamicum |
Thelesperma |
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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 |
AR; AZ; CO; KS; NE; NM; OK; SD; TX; UT; WY; South America; Mexico (Chihuahua, Coahuila)
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w North America; Mexico; South America |
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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.) |
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Key |
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Source | FNA vol. 21, p. 202. | FNA vol. 21, p. 199. | ||||||||||||||||||||||||||||||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Coreopsidinae > Thelesperma | Asteraceae > tribe Heliantheae > subtribe Coreopsidinae | ||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||
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Synonyms | Bidens megapotamica, T. gracile | |||||||||||||||||||||||||||||||||
Name authority | (Sprengel) Kuntze: Revis. Gen. Pl. 3(2): 182. (1898) | Lessing: Linnaea 6: 511. (1831) | ||||||||||||||||||||||||||||||||
Web links |