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Santa Rita Mountain ticktrefoil

Santa Cruz Island ticktrefoil

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

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

erect or ascending, branched, 40–100 cm, slightly uncinate-pubescent and pilose or 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 mostly persistent, broadly ovate, 4–10 mm, base subamplexicaul;

petiole 30–40 mm;

leaflet blades broadly ovate-elliptic or ovate to narrowly ovate, apex acute, surfaces uncinate-puberulent;

terminal blade 20–70(–100) × 10–20(–50) mm, length 1.8–2 times width.

Inflorescences

usually unbranched, sometimes branched;

rachis patent uncinate-puberulent;

primary bracts narrowly ovate, 2.5–3 mm.

branched or unbranched;

rachis bulbous-villous and uncinate-puberulent;

primary bracts caducous, subulate, 1 mm.

Pedicels

8–15 mm.

10–20 mm, patent uncinate-pubescent.

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 1.5–2 mm, pilose and uncinate-puberulent, tube 0.8 mm;

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

corolla pink-purple, fading greenish, 4–5 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 subequally deeply crenate;

connections central, 1/8–1/7 as broad as segments;

segments 3–6, rounded, 6–10 × 5–7 mm, rounded, sparsely pubescent, at least on sutures;

stipe 1(–2) mm.

Desmodium retinens

Desmodium psilocarpum

Phenology Flowering late summer–fall. Flowering late summer–fall.
Habitat Wooded or grassy rocky slopes, oak or oak-pine forests. Woodland, grasslands, canyon slopes, streamsides.
Elevation 1400–2100 m. (4600–6900 ft.) 1000–2000 m. (3300–6600 ft.)
Distribution
from FNA
AZ; Mexico; Central America (Guatemala)
[BONAP county map]
from FNA
AZ; NM; Mexico (Chihuahua, Nuevo León, Sonora, Tamaulipas)
[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.)

Desmodium psilocarpum is known in the flora area from southern Arizona and adjacent southwestern New Mexico.

(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. 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. 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 Meibomia psilocarpa
Name authority Schlechtendal: Linnaea 12: 311. (1838) A. Gray: Smithsonian Contr. Knowl. 5(6): 48. (1853)
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