Desmodium tweedyi |
Desmodium marilandicum |
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Tweedy's ticktrefoil |
Maryland tickclover, smooth small-leaf tick-trefoil |
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Habit | Herbs, perennial. | Herbs, perennial. | ||||||||
Stems | ascending or erect, usually striate, angled, 30–100 cm, densely uncinate-puberulent to -pubescent and sparsely glutinous-pilose. |
ascending to erect, usually striate, branched or unbranched, 30–150 cm, glabrous or sparsely to densely uncinate-puberulent, sometimes also patent long-pilose. |
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Leaves | trifoliolate; stipules persistent, ovate, 7.5–14.5 mm; petiole 40–90 mm; leaflet blades narrowly ovate to ovate or broadly ovate, thick, leathery, apex acute, usually pale-blotched along midrib adaxially, surfaces uncinate-puberulent to -pubescent and villous; terminal blade 40–120 × 20–66 mm, length 2 times width. |
trifoliolate; stipules caducous or moderately persistent, subulate to narrowly ovate, 2–5 mm; petiole 1–30 mm; leaflet blades narrowly ovate, elliptic, elliptic-ovate, ovate-rhombic, or suborbiculate, apex obtuse or acute, mucronulate, surfaces sparsely to densely uncinate-puberulent and appressed-villous abaxially, uncinate-puberulent or glabrescent adaxially; terminal blade 9–75 × 6–33 mm, length 1.5–4(–5) times width. |
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Inflorescences | branched or unbranched; rachis densely uncinate-puberulent to -pubescent and glutinous-villous; primary bracts ovate to broadly ovate, 7–10 mm. |
terminal and branched, axillary and unbranched; rachis uncinate-puberulent; primary bracts ovate, 1.5–3 mm. |
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Pedicels | 8–25 mm, patent uncinate-pubescent and pilose. |
3–19 mm, uncinate-puberulent. |
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Flowers | calyx 3–5 mm, puberulent and pubescent, ± glutinous, tube 1.2–1.5 mm; abaxial lobes 2.5–4 mm, lateral lobes 1.5 mm; corolla white, 7–8 mm. |
calyx 1.5–2.5 mm, pubescent (not uncinate-puberulent), tube 1 mm; abaxial lobes 1.2–1.5 mm, lateral lobes 1 mm; corolla usually lavender to red-violet or pink-purple, rarely white, 4–6 mm. |
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Loments | sutures nearly equally crenate; connections adaxial, 1/4 as broad as segments; segments (2 or)3–5(or 6), subrhombic, 6–8 × 4 mm, obtusely angled abaxially, somewhat angled adaxially, densely uncinate-pubescent throughout; stipe 2–4 mm. |
sutures crenate abaxially, sinuate adaxially; connections adaxial, 1/4–1/2 as broad as segments; segments 1–4, broadly elliptic, 3.5–5.5 × 2.5–4 mm, rounded abaxially, convex adaxially, uncinate-puberulent throughout; stipe 1–2 mm. |
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2n | = 22. |
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Desmodium tweedyi |
Desmodium marilandicum |
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Phenology | Flowering early summer. | |||||||||
Habitat | Woodlands near creeks, usually calcareous soils. | |||||||||
Elevation | 200–800 m. (700–2600 ft.) | |||||||||
Distribution |
OK; TX |
e United States; sc United States; West Indies
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Discussion | Desmodium tweedyi is known from the Edwards Plateau area and north-central Texas northward to central Oklahoma. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Varieties 3 (3 in the flora). Desmodium ciliare, D. lancifolium, and D. marilandicum have generally been recognized as closely related but distinct species in floras of the United States. They commonly have two or three articulate, small loments. D. Isely (1990, 1998) grouped them as the D. ciliare Group and regarded forms intermediate between them as putative hybrids: D. ciliare × D. marilandicum and D. ciliare × D. lancifolium. They have been separated by differences in the leaflets and pubescence, but the differences are not always clear. They are treated here as one species with three varieties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 11. | FNA vol. 11. | ||||||||
Parent taxa | ||||||||||
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Synonyms | Meibomia tweedyi | Hedysarum marilandicum, Meibomia marilandica | ||||||||
Name authority | Britton: Trans. New York Acad. Sci. 9: 183. (1890) | (Linnaeus) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle: Prodr. 2: 328. (1825) — (as marylandicum) | ||||||||
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