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large-bract tick-trefoil

scorpion ticktrefoil

Habit Herbs, perennial. Herbs, perennial.
Stems

erect or ascending, usually striate, 50–150 cm, usually glabrous, sometimes sparsely uncinate-pubescent or pilose.

slender, procumbent or decumbent, 20–100 cm, densely patent uncinate-puberulent and/or inconspicuously pilose.

Leaves

trifoliolate;

stipules usually persistent, narrowly ovate or subulate, 10–20 mm;

petiole 40–70 mm;

leaflet blades ovate to broadly ovate, apex sharply acuminate to shortly cuspidate, surfaces glabrous (except veins spreading-villosulous);

terminal blade 50–120 × 30–70 mm, length 1.5–3 times width.

trifoliolate;

stipules persistent, obliquely ovate, 2–3.5 mm, base auriculate, amplexicaul;

petiole 10–20 mm;

leaflet blades usually ovate to shortly elliptic, rarely narrowly elliptic, apex obtuse, surfaces appressed-pubescent;

terminal blade usually 10–35(–50) × 7–30 mm, length (1.5–)2–3 times width.

Inflorescences

branched;

rachis densely uncinate-pubescent to rarely glabrescent;

primary bracts conspicuously covering apex of inflorescences, narrowly ovate, 8–14 mm.

lax-flowered, terminal and axillary, usually unbranched;

rachis densely spreading-pubescent;

primary bracts caducous, narrowly ovate, 1.5–2 mm.

Pedicels

4–8 mm, densely patent uncinate-puberulent and sparsely pilose.

3–10 mm.

Flowers

calyx 3–4 mm, glabrate, margins sparsely ciliate, lobes pilose, tube 1.5–2 mm;

abaxial lobes 3–4 mm, lateral lobes 2–3 mm;

corolla purple, 8–12 mm.

calyx 1.5–2.5 mm, pilose, tube 1 mm;

abaxial lobes 1.5 mm, lateral lobes 0.7–1 mm;

corolla lavender-pink or reddish purple, banner with yellow spots, 4–5 mm.

Loments

sutures dentate abaxially, sinuate adaxially;

connections adaxial, 1/2 as broad as segments;

segments (1–)4–7, obliquely narrow-rhombic or suborbiculate, (7–)9–11 × 4–5 mm, angled abaxially, slightly convex adaxially, sparsely uncinate-puberulent, sutures densely uncinate-puberulent;

stipe 1–2.5 mm.

turgid, straight or curved, linear;

sutures equally shallow-undulate;

connections central, 2/3–3/4 as broad as segments;

segments 5–10, narrowly oblong or narrowly elliptic, 4–5 × 1.5 mm, rugose, not reticulate, symmetrically convex abaxially and adaxially, densely uncinate-pubescent throughout;

stipe 1 mm.

Desmodium cuspidatum

Desmodium scorpiurus

Phenology Flowering summer–fall. Flowering year-round.
Habitat Rich, moist woodlands, thickets, openings, dry, rocky woodlands, ruderal areas. Waste places, lawns.
Elevation 0–1000 m. (0–3300 ft.) 0–10 m. (0–0 ft.)
Distribution
from FNA
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MN; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WI; WV; ON
[WildflowerSearch map]
[BONAP county map]
from FNA
FL; Central America; South America; Mexico (Durango, Guerrero, Guanajuato, Jalisco, Michoacán, Oaxaca, Sonora, Veracruz); West Indies [Introduced in North America; introduced also in Asia, Africa, Pacific Islands, Australia]
[BONAP county map]
Discussion

In Texas, Desmodium cuspidatum is known only from Bowie County, at the northeastern corner of the state.

(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. 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. tweedyi, 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. sessilifolium, D. strictum, D. tenuifolium, D. tortuosum, D. triflorum, D. tweedyi, D. viridiflorum, D. ×humifusum
Synonyms Hedysarum cuspidatum, D. bracteosum, D. cuspidatum var. longifolium, D. grandiflorum, Meibomia grandiflora, M. longifolia Hedysarum scorpiurus, Meibomia scorpiurus
Name authority (Muhlenberg ex Willdenow) de Candolle ex G. Don in J. C. Loudon: Hort. Brit., 309. (1830) (Swartz) Poiret in F. Cuvier: Dict. Sci. Nat. ed. 2, 13: 110. (1819)
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