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Tweedy's ticktrefoil

slimleaf tick trefoil

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 or erect, 50–100 cm, inconspicuously uncinate-puberulent.

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, narrowly deltate, 3 mm, glabrous;

petiole 5–20 mm;

leaflet blades linear, leathery, usually folded and appearing narrower, apex acute or obtuse, surfaces reticulate-veined adaxially, glabrous or sparsely puberulent abaxially, glabrous adaxially;

terminal blade 30–60(–80) × 5–7 mm, length 8–10 times width.

Inflorescences

branched or unbranched;

rachis densely uncinate-puberulent to -pubescent and glutinous-villous;

primary bracts ovate to broadly ovate, 7–10 mm.

branched or unbranched;

rachis uncinate-pubescent and villous;

primary bracts ovate, 2.5 mm.

Pedicels

8–25 mm, patent uncinate-pubescent and pilose.

5–10 mm.

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 mm, uncinate-puberulent, tube 0.8–1 mm;

abaxial lobes 1 mm, lateral lobes 0.7–0.8 mm;

corolla pink, 4–5 mm.

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, 1/3–1/2 as broad as segments;

segments (1 or)2 or 3, semiorbiculate, 3.5–5 × 3 mm, symmetrically rounded abaxially, convex adaxially, densely uncinate-puberulent throughout;

stipe 0.5–3 mm.

Desmodium tweedyi

Desmodium tenuifolium

Phenology Flowering early summer. Flowering late summer.
Habitat Woodlands near creeks, usually calcareous soils. Moist pine savannas, grass-sedge marshes, pocosins, borders, alluvial woodlands, ditches, moist ruderal areas.
Elevation 200–800 m. (700–2600 ft.) 0–100 m. (0–300 ft.)
Distribution
from FNA
OK; TX
[BONAP county map]
from FNA
AL; FL; GA; LA; MD; MS; NC; SC; VA
[WildflowerSearch map]
[BONAP county map]
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.)

Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Desmodium Fabaceae > subfam. Faboideae > Desmodium
Sibling taxa
D. arizonicum, D. batocaulon, D. canadense, D. canescens, D. cinerascens, D. cuspidatum, D. floridanum, D. grahamii, D. gramineum, D. illinoense, D. incanum, D. intortum, D. laevigatum, D. lindheimeri, D. lineatum, D. marilandicum, D. metcalfei, D. nuttallii, D. ochroleucum, D. paniculatum, D. procumbens, D. psilocarpum, D. psilophyllum, D. retinens, D. rosei, D. rotundifolium, D. scopulorum, D. scorpiurus, D. sessilifolium, D. strictum, D. tenuifolium, D. tortuosum, D. triflorum, D. viridiflorum, D. ×humifusum
D. arizonicum, D. batocaulon, D. canadense, D. canescens, D. cinerascens, D. cuspidatum, D. floridanum, D. grahamii, D. gramineum, D. illinoense, D. incanum, D. intortum, D. laevigatum, D. lindheimeri, D. lineatum, D. marilandicum, D. metcalfei, D. nuttallii, D. ochroleucum, D. paniculatum, D. procumbens, D. psilocarpum, D. psilophyllum, D. retinens, D. rosei, D. rotundifolium, D. scopulorum, D. scorpiurus, D. sessilifolium, D. strictum, D. tortuosum, D. triflorum, D. tweedyi, D. viridiflorum, D. ×humifusum
Synonyms Meibomia tweedyi Meibomia tenuifolia
Name authority Britton: Trans. New York Acad. Sci. 9: 183. (1890) Torrey & A. Gray: Fl. N. Amer. 1: 363. (1840)
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