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Photo is of parent taxon

panicledleaf ticktrefoil

arrow-leaf tick-trefoil, panicle tick-trefoil, panicle tickclover, panicledleaf ticktrefoil

Habit Herbs, perennial; base woody, rootstock thick.
Stems

and petioles glabrescent to conspicuously pilose or uncinate-pubescent.

erect or ascending, usually striate, 30–100(–150) cm, glabrous or sparsely to densely uncinate-puberulent or conspicuously pilose or glabrescent.

Leaves

trifoliolate;

stipules caducous, subulate to narrowly ovate-deltate, 2–6 mm;

petiole (10–)20–50 mm;

leaflet blades polymorphic, linear, narrowly ovate, narrowly ovate-oblong, ovate, broadly ovate to subrounded, or rhombic, usually thin, rarely thick, papery, apex acute to obtuse, surfaces closely to subdensely appressed pilose, inconspicuously reticulate-veined abaxially, sparsely appressed-puberulent and pilose adaxially;

terminal blade 20–100 × 8–65 mm, length 1–8 times width.

Leaflets

blade surfaces slightly strigose to conspicuously subappressed-villous, sometimes uncinate-pubescent abaxially.

Inflorescences

terminal panicles and axillary racemes, branched, very diffuse;

rachis moderately to densely uncinate-puberulent to -pubescent;

primary bracts narrowly ovate, 1–3.5 mm.

Pedicels

(3–)6–12(–20) mm.

Flowers

calyx 2–3 mm, pubescent, tube 1–1.5 mm;

abaxial lobes 2 mm, lateral lobes 1 mm;

corolla lilac to purple, 6–9 mm.

Loments

sutures deeply crenate or dentate abaxially, sinuate adaxially;

connections adaxial, 1/5–1/3 as broad as segments;

segments (2 or)3–5, deltate to rhombic, (4–)5–10 × 3–5 mm, angled abaxially (sometimes obtusely), convex adaxially, uncinate-puberulent to -pubescent;

stipe 1–7 mm.

2n

= 22.

Desmodium paniculatum var. paniculatum

Desmodium paniculatum

Phenology Flowering summer–fall.
Habitat Woodlands and margins, low, moist alluvial sites, dry slopes, uplands, clearings, fields, thickets, roadsides.
Elevation 0–1000 m. (0–3300 ft.)
Distribution
from FNA
AL; AR; CT; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; ME; MI; MO; MS; NC; NE; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; VT; WI; WV; ON; QC [Introduced in e Asia (Japan)]
from USDA
North America [Introduced in e Asia (Japan)]
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

Desmodium paniculatum is allied with D. fernaldii, D. glabellum, and D. perplexum, and the four are called the D. paniculatum Group, which is characterized by having straight loments with 3–5 angled segments. These species have been studied intensively by B. G. Schubert (1950, 1950b) and D. Isely (1953, 1983b, 1990, 1998). According to Isely (1990, 1998), D. paniculatum intergrades with both D. perplexum and D. glabellum, resulting in a continuum of variation among the members of the D. paniculatum Group that suggests introgression, including: D. paniculatum × D. perplexum; D. paniculatum × D. glabellum; and D. glabellum × D. perplexum. They are treated here as varieties of a single polymorphic species. The varieties are distinguished by somewhat continuous or overlapping characters.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Leaflet blade surfaces slightly strigose to conspicuously subappressed-villous, sometimes uncinate-pubescent abaxially; stems and petioles glabrescent to conspicuously pilose or uncinate-pubescent.
var. paniculatum
1. Leaflet blade surfaces uncinate-puberulent on veins, sparsely strigulose abaxially; stems and petioles glabrous or uncinate-pubescent.
var. fernaldii
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Desmodium > Desmodium paniculatum Fabaceae > subfam. Faboideae > Desmodium
Sibling taxa
D. paniculatum var. fernaldii
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. 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
Subordinate taxa
D. paniculatum var. fernaldii, D. paniculatum var. paniculatum
Synonyms D. dichromum, D. dillenii, D. glabellum, D. paniculatum var. angustifolium, D. paniculatum var. dillenii, D. paniculatum var. epetiolatum, D. perplexum, D. pubens, Hedysarum glabellum, Meibomia chapmanii, M. dillenii, M. glabella, M. pubens Hedysarum paniculatum, Meibomia paniculata
Name authority unknown (Linnaeus) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle: Prodr. 2: 329. (1825)
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