Tetraneuris ivesiana |
Tetraneuris |
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Ives' four-nerve-daisy |
bitterweed, four-nerve daisy |
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Habit | Perennials, 10–26+ cm. | Annuals or perennials, 2–50+ cm (perennials with ± branched, woody caudices). | ||||||||||||||||||||||||||||||||
Caudices | ± branched, branches notably thickened distally. |
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Stems | (1–)5–20(–30), erect, leafy, ± branched distally. |
1–60, erect or ± decumbent, unbranched or sparingly branched distally. |
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Leaves | basal and cauline, entire, glabrous or sparsely to moderately lanuginose to sericeous, usually densely gland-dotted; basal leaves tightly clustered, blades linear-oblanceolate; proximal cauline blades linear-oblanceolate; mid blades linear-oblanceolate to linear, 1.7–2 mm wide; distal blades linear-oblanceolate to linear. |
all basal, or basal-proximal, or basal and cauline; alternate; petiolate or sessile; blades (usually with distinct midribs) mostly oblanceolate to linear or filiform, sometimes lobed, ultimate margins usually entire, sometimes toothed, faces glabrous or ± hairy, eglandular or ± gland-dotted. |
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Peduncles | 5–18.5 cm, ± hairy, usually densely hairy distally. |
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Involucres | 8–12 × 13–17 mm. |
hemispheric to campanulate 6–20 mm diam. |
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Receptacles | hemispheric to conic, shallowly pitted or smooth, epaleate. |
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Ray florets | 7–10; corollas 10–20 mm. |
0 or 7–27, pistillate, fertile; corollas (usually marcescent) yellow (laminae fan-shaped to oblanceolate, usually 3-lobed). |
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Disc florets | (40–)80–150+; corollas yellow, 3.3–4.5 mm. |
20–250+, bisexual, fertile; corollas yellow proximally, yellow or purplish distally, tubes shorter than cylindric to cylindro-campanulate throats, lobes 5, ± deltate. |
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Phyllaries | 11–60+ in 3 series (mostly spreading to erect in fruit, distinct, herbaceous; outer with or without scarious margins, abaxial faces ± hairy; mid usually same number as, alternating with, and similar to outer, almost always with ± scarious margins; inner narrower than others, margins scarious). |
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Outer phyllaries | 7–12, 5–6.4 mm, margins 0–0.3(–0.4) mm wide, usually scarious, abaxial faces ± hairy. |
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Heads | (1–)5–30(–40) per plant (1–5 per stem), borne singly or in paniculiform to corymbiform arrays. |
radiate or discoid, borne singly or in paniculiform to corymbiform or fastigiate arrays. |
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Cypselae | 3–4.1 mm; pappi of 5–7 lanceolate or obovate to oblanceolate, aristate scales 2.7–4.5 mm. |
± obpyramidal, moderately to densely hairy; pappi persistent, of 4–8 usually aristate, scales. |
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x | = 15. |
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2n | = 28, 30, 56, 60. |
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Tetraneuris ivesiana |
Tetraneuris |
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Phenology | Flowering Apr–Aug. | |||||||||||||||||||||||||||||||||
Habitat | Roadsides, hillsides, open treeless areas, edges of woods | |||||||||||||||||||||||||||||||||
Elevation | 1300–2900 m (4300–9500 ft) | |||||||||||||||||||||||||||||||||
Distribution |
AZ; CO; NM; UT
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North America; Mexico |
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Discussion | Species 9 (9 in the flora). Here, strigoso-canescent refers to often silvery induments (hairs tightly appressed, relatively short, 1–1.5 mm) of Tetraneuris argentea and T. acaulis var. acaulis. Such induments contrast with lanuginose or sericeous induments (hairs spreading, ca 1.5–3 mm) in other taxa, including T. ivesiana and the other three varieties of T. acaulis. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 21, p. 450. | FNA vol. 21, p. 447. | ||||||||||||||||||||||||||||||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Gaillardiinae > Tetraneuris | Asteraceae > tribe Heliantheae > subtribe Gaillardiinae | ||||||||||||||||||||||||||||||||
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Synonyms | Hymenoxys acaulis var. ivesiana, Hymenoxys argentea var. ivesiana, Hymenoxys ivesiana, T. intermedia, T. mancosensis, T. pilosa | |||||||||||||||||||||||||||||||||
Name authority | Greene: Pittonia 3: 269. (1898) | Greene: Pittonia 3: 265. (1898) | ||||||||||||||||||||||||||||||||
Web links |