Tetraneuris linearifolia |
Tetraneuris |
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fineleaf fournerve daisy, slimleaf actinea |
bitterweed, four-nerve daisy |
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Habit | Annuals, 16–50+ cm. | Annuals or perennials, 2–50+ cm (perennials with ± branched, woody caudices). | ||||||||||||||||||||||||||||||||||||
Caudices | none. |
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Stems | 1–10, erect or ± decumbent, leafy, unbranched or branched distally. |
1–60, erect or ± decumbent, unbranched or sparingly branched distally. |
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Leaves | basal and cauline, ± hairy, ± gland-dotted; basal blades spatulate to oblanceolate, entire or with 2–6 teeth or lobes; proximal cauline blades narrowly spatulate or oblanceolate to linear-oblanceolate, entire or with 2–6 teeth or lobes; mid blades oblanceolate to linear-oblanceolate to linear, 0.9–9.5(–16) mm wide, entire or with 1–2 teeth or lobes; distal blades narrowly oblanceolate to linear-oblanceolate to linear, entire or with 1–2 teeth or lobes. |
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 | 8–29 cm, ± hairy. |
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Involucres | 5–10 × 7–15 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 | 9–25; corollas 8.2–16.8 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 | 50–200+; corollas yellow, 1.6–3 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 | 8–21, 2.4–5.5 mm, margins 0–0.2 mm wide, not scarious or scarious, abaxial faces ± hairy. |
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Heads | 8–50(–80) per plant, borne singly or in corymbiform arrays. |
radiate or discoid, borne singly or in paniculiform to corymbiform or fastigiate arrays. |
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Cypselae | 1.5–2.6 mm; pappi of 4–8 obovate, often aristate scales 1–2.5 mm. |
± obpyramidal, moderately to densely hairy; pappi persistent, of 4–8 usually aristate, scales. |
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x | = 15. |
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Tetraneuris linearifolia |
Tetraneuris |
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Distribution |
KS; NM; OK; TX; n Mexico
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North America; Mexico |
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Discussion | Varieties 2 (2 in the flora). Plants of Tetraneuris linearifolia morphologically intermediate between the two varieties are found in Bee, Duval, Live Oak, and McMullen counties, Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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. 448. | FNA vol. 21, p. 447. | ||||||||||||||||||||||||||||||||||||
Parent taxa | Asteraceae > tribe Heliantheae > subtribe Gaillardiinae > Tetraneuris | Asteraceae > tribe Heliantheae > subtribe Gaillardiinae | ||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||
Synonyms | Hymenoxys linearifolia | |||||||||||||||||||||||||||||||||||||
Name authority | (Hooker) Greene: Pittonia 3: 269. (1898) | Greene: Pittonia 3: 265. (1898) | ||||||||||||||||||||||||||||||||||||
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