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sessile tickclover, sessile-leaf tick-trefoil, sessileleaf tickclover

Nuttall's ticktrefoil

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

ascending to erect, usually striate, mostly unbranched, 50–100(–150) cm, medially uncinate-puberulent and uncinate-pubescent.

ascending to erect, 30–100 cm, medially villous, uncinate-puberulent and -pubescent, scarcely pilose.

Leaves

trifoliolate;

stipules moderately persistent, narrowly ovate, 4–9.5 mm, apex often awn-tipped;

petiole 1–5 mm;

leaflet blades narrowly elliptic to linear, apex obtuse or acute, surfaces prominently reticulate-veined abaxially, uncinate-puberulent and subappressed pubescent abaxially, glabrate or sparsely pubescent adaxially;

terminal blade (30–)40–85 × 5–15 mm, length 4–10 times width.

trifoliolate;

stipules persistent, narrowly ovate or ovate, 3–6.5 mm;

petiole 5–30 mm;

leaflet blades ovate to narrowly ovate, base usually rounded, apex obtuse or acute, surfaces closely spreading-villous (often velvety) abaxially, slightly uncinate-puberulent on veins adaxially;

terminal blade 50–100 × 30–56 mm, length 1.5–2(–2.2) times width.

Inflorescences

terminal and branched;

rachis terete to subangulate, densely uncinate-puberulent and sparsely pilose;

primary bracts ovate, 2.5–3 mm.

terminal and branched;

rachis patent uncinate-puberulent and pilose;

primary bracts ovate, 2–4 mm, usually villous.

Pedicels

2–5 mm.

4–10 mm.

Flowers

calyx 2.5–3 mm, puberulent, tube 1.5 mm;

abaxial lobes ovate, 1.5 mm, lateral lobes ovate, 1 mm;

corolla pale lavender to reddish purple, 5 mm.

calyx 2–3 mm, puberulent and sparsely pilose, tube 1 mm;

abaxial lobes 1.5–2 mm, lateral lobes 1 mm;

corolla purple or pink, 6–7 mm.

Loments

sutures deeply crenate abaxially, sinuate adaxially;

connections adaxial, 1/3 as broad as segments;

segments (1 or)2(–4), semiorbiculate, 4.5–6 × 3–4.5 mm, symmetrically rounded abaxially, nearly straight or convex adaxially, densely uncinate-puberulent throughout;

stipe 1–3 mm.

sutures deeply crenate abaxially, sinuate adaxially;

connections adaxial, 1/4–1/3 as broad as segments;

segments 2–4, semiorbiculate, 4–7 × 3–4.5 mm, rounded abaxially, convex adaxially, often somewhat angled when young, uncinate-pubescent throughout;

stipe 3–4 mm.

2n

= 22.

Desmodium sessilifolium

Desmodium nuttallii

Phenology Flowering summer–fall. Flowering summer–fall.
Habitat Open, dry upland woods, abandoned fields, roadsides. Open woodlands and bor­ders, savannas, fields, roadsides.
Elevation 0–500 m. (0–1600 ft.) 0–900 m. (0–3000 ft.)
Distribution
from FNA
AL; AR; CT; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NC; NE; NJ; OH; OK; PA; RI; SC; TN; TX; VA
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; DE; FL; GA; IL; IN; KY; LA; MD; MO; MS; NC; NJ; NY; OH; OK; PA; SC; TN; TX; VA; WV
[WildflowerSearch map]
[BONAP county map]
Discussion

Desmodium sessilifolium is considered extirpated from Ontario.

(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. 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. 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
Synonyms Meibomia sessilifolia Meibomia nuttallii
Name authority Torrey & A. Gray: Fl. N. Amer. 1: 363. (1840) (Schindler) B. G. Schubert: Rhodora 52: 142. (1950)
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