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Santa Rita Mountain ticktrefoil

Canada tickclover, Canadian tick-trefoil, showy tick-trefoil

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

erect, ascending, or procumbent, usually striate, 30–60(–100) cm, sparsely to densely pilose and uncinate-pubescent.

erect, 50–100 cm, sparsely to densely pilose or villous, usually patent uncinate-puberulent and -pubescent, sometimes glabrescent.

Leaves

trifoliolate, sometimes unifoliolate proximally;

stipules persistent, recurved, subulate, 2–3 mm;

petiole 7–25 mm;

leaflet blades usually oblong-ovate to narrowly so, sometimes broadly elliptic to oblong, apex obtuse or acute, surfaces sparsely uncinate-puberulent;

terminal blade 10–30(–35) × 8–10 mm, length 1–3.5 times width.

trifoliolate;

stipules ± persistent, subulate to narrowly ovate, 4.5–9.5 mm;

petiole 10–60 mm;

leaflet blades often pale green abaxially, ovate to narrowly ovate, apex acute, surfaces slightly or visibly strigulose abaxially, sparsely puberulent or nearly glabrescent adaxially;

terminal blade 40–110 × 15–30 mm, length 2.5–3.5 times width.

Inflorescences

usually unbranched, sometimes branched;

rachis patent uncinate-puberulent;

primary bracts narrowly ovate, 2.5–3 mm.

terminal and branched, or unbranched from distal axils;

rachis villous and uncinate-pubescent, sometimes appearing glabrescent;

primary bracts caducous, narrowly ovate, 6–7 mm.

Pedicels

8–15 mm.

4–8 mm.

Flowers

calyx 1.5–2.5 mm, pubescent, tube 1 mm;

abaxial lobes 1.5 mm, lateral lobes 1 mm;

corolla pink-purple, 4–5 mm.

calyx 3.5–5 mm, densely uncinate-puberulent and sparsely pilose, tube 1–1.5 mm;

abaxial lobes 3–3.5 mm, lateral lobes 2 mm;

corolla usually blue-violet, rarely white, 8–11 mm.

Loments

sutures subequally crenate;

connections central, 1/5–1/4 as broad as segments;

segments 2–7, rounded or broadly elliptic, 2.5–3 × 2.5 mm, abaxially and adaxially rounded, glabrous or slightly puberulent;

stipe 1–2 mm.

sutures crenate abaxially, repand or sinuate adaxially;

connections adaxial, 1/2 as broad as segments;

segments 3–5, semiorbiculate, 4–8 × 4–5 mm, rounded abaxially, convex adaxially, densely uncinate-puberulent;

stipe 2(–3) mm.

2n

= 22.

Desmodium retinens

Desmodium canadense

Phenology Flowering late summer–fall. Flowering summer.
Habitat Wooded or grassy rocky slopes, oak or oak-pine forests. Prairie relics, woodland borders and openings, roadsides.
Elevation 1400–2100 m. (4600–6900 ft.) 0–900 m. (0–3000 ft.)
Distribution
from FNA
AZ; Mexico; Central America (Guatemala)
[BONAP county map]
from FNA
CT; DE; IA; IL; IN; KS; MA; MD; ME; MI; MN; MO; ND; NH; NJ; NY; OH; OK; PA; RI; SD; TX; VA; VT; WI; WV; MB; NB; NS; ON; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

Desmodium retinens is known in the flora area from Cochise, Graham, Pima, and Santa Cruz counties.

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

In Texas, Desmodium canadense is known only from Wheeler County.

(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. 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. 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. tweedyi, D. viridiflorum, D. ×humifusum
Synonyms D. wislizeni, Meibomia retinens Hedysarum canadense, Meibomia canadensis
Name authority Schlechtendal: Linnaea 12: 311. (1838) (Linnaeus) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle: Prodr. 2: 328. (1825)
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