Desmodium gramineum |
Desmodium tortuosum |
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grassleaf ticktrefoil |
Dixie tick trefoil |
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Habit | Herbs, perennial. | Herbs, perennial. |
Stems | stiffly erect or ascending, branched at base and appearing clustered, 40–80 cm, glabrescent or sparsely uncinate-puberulent. |
erect, 50–200 cm, medially uncinate-pubescent and patent-villous. |
Leaves | unifoliolate; stipules caducous, narrowly ovate, 3–9 mm; petiole 10–30 mm; leaflet blades linear, (40–)70–130 × 2–5 mm, length 10+ times width, apex acute or acuminate, surfaces uncinate-puberulent and sparsely strigose on veins abaxially, uncinate-puberulent adaxially. |
trifoliolate; stipules persistent, often patent or reflexed, obliquely ovate and apex acuminate or narrowly ovate and apex aristate, 3–12.5 mm, base amplexicaul; petiole 8–50 mm; leaflet blades narrowly ovate to ovate, elliptic, or rhombic, apex obtuse or acute, surfaces obscurely prominently reticulate-veined abaxially, uncinate-puberulent and strigose or subappressed-villous; terminal blade (20–)40–150 × 10–50 mm, length 2–3 times width. |
Inflorescences | branched or unbranched; rachis sparsely uncinate-puberulent; primary bracts ovate, 2–3 mm. |
branched or unbranched; rachis villous (often with bulbous hairs) and uncinate-puberulent, or only uncinate-puberulent; primary bracts caducous, narrowly ovate, 4 mm. |
Pedicels | 10–20 mm, uncinate-puberulent or glabrescent. |
10–15 mm. |
Flowers | calyx 2 mm, puberulent and uncinate-puberulent, tube 0.8 mm; abaxial lobes 1.2 mm, lateral lobes 1 mm; corolla ephemeral, purple, 3 mm. |
calyx 1.5–3 mm, uncinate-puberulent, tube to 1 mm; abaxial lobes 2 mm, lateral lobes 1 mm; corolla lavender, 4–6 mm. |
Loments | margins slightly involute, sutures equally crenate; connections central, 1/4 as broad as segments; segments 3–6, broadly elliptic, (2–)3–3.5 × 2.5–3 mm, convex or rounded abaxially and adaxially, sparsely uncinate-puberulent, sutures moderately uncinate-puberulent; stipe to 1 mm. |
margins alternately involute and revolute, sutures equally crenate, twisted conspicuously when young; connections central, 1/4 as broad as segments; segments (3 or)4–7, orbiculate, broadly elliptic, or rhombic, 3–4.5 × 3–3.5 mm, rounded abaxially and adaxially, densely uncinate-pubescent; stipe 0.5–1 mm. |
2n | = 22. |
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Desmodium gramineum |
Desmodium tortuosum |
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Phenology | Flowering late summer–fall. | Flowering summer–fall (year-round). |
Habitat | Dry woodlands, grasslands, open hillsides. | Open, disturbed sites, ruderal areas, pinelands, savannas. |
Elevation | 1100–1500 m. (3600–4900 ft.) | 0–300 m. (0–1000 ft.) |
Distribution |
AZ; Mexico (Chihuahua, Colima, Jalisco, Michoacán, Oaxaca, Sinaloa, Sonora, Tamaulipas) |
AL; AR; FL; GA; LA; MS; NC; SC; TX; Central America; South America; Mexico (Chiapas, Colima, Guerrero, Jalisco, Nayarit, Oaxaca, Sinaloa, Sonora); West Indies [Introduced in North America; introduced also in Asia, Africa, Indian Ocean Islands, Pacific Islands, Australia]
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Discussion | In Arizona, Desmodium gramineum is known from Cochise, Pima, Pinal, and Santa Cruz counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Desmodium tortuosum is most easily distinguished from its relatives by the thick leaflets with prominent reticulate venation, the large persistent stipules, and the long, stiff, ascending to spreading pedicels (B. G. Schubert 1980). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | D. angustifolium var. gramineum, Meibomia graminea | Hedysarum tortuosum, Meibomia purpurea, M. tortuosa |
Name authority | A. Gray: Smithsonian Contr. Knowl. 5(6): 46. (1853) | (Swartz) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle: Prodr. 2: 332. (1825) |
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