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creeping beggarweed, Spanish clover, Spanish tick-trefoil, zarzabacoa comun

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

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

erect or ascending, to 300 cm, pubescent or glabrescent.

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

Leaves

trifoliolate;

stipules usually persistent, narrowly ovate-deltate, 5–10 mm;

petiole usually 15–20 mm;

leaflet blades elliptic to ovate, apex obtuse or acute, surfaces finely spreading-villosulous to substrigose abaxially, uncinate-puberulent or glabrescent adaxially;

terminal blade 20–90 × 15–45 mm, length 1.5–4 times width.

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.

Inflorescences

unbranched;

rachis densely patent uncinate-pubescent;

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

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

persistent with calyx-remnant at top after loments drop, 5–9 mm.

(3–)6–12(–20) mm.

Flowers

calyx 2–3.5 mm, uncinate-puberulent, lobes pilose, tube 1 mm;

abaxial lobes 1.5–2.5 mm, lateral lobes 1–2 mm;

corolla purple, 5–8 mm.

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 symmetrically crenate abaxially, straight or slightly sinuate adaxially;

connections central, 1/2–2/3 as broad as segments;

segments 4–8, semiobovate, 3.5–5 × 2.5–3 mm, broadly rounded abaxially, straight or barely convex adaxially, uncinate-puberulent;

stipe 1.5–2 mm.

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.

= 22.

Desmodium incanum

Desmodium paniculatum

Phenology Flowering spring–fall.
Habitat Pine-palmetto flatwoods, woodland borders, lawns, ruderal sites, disturbed or waste areas.
Elevation 0–50 m. [0–160 ft.]
Distribution
map from FNA
AL; FL; GA; TX; Central America; South America; Mexico (Chiapas, Jalisco, Oaxaca, Quintana Roo, Tamaulipas, Veracruz); West Indies [Introduced in North America; introduced also in Asia (Taiwan), Africa, Indian Ocean Islands (Mauritius, Reunion), Pacific Islands, Australia]
[WildflowerSearch map]
[BONAP county map]
map from USDA
North America [Introduced in e Asia (Japan)]
[WildflowerSearch map]
[BONAP county map]
Discussion

Desmodium incanum may be distinguished by its long-persistent stipules usually fused and nearly surrounding the stem, at least when young, and by its pedicels which are usually borne singly and are each subtended by one primary bract and two (lateral) secondary bracts (B. G. Schubert 1980).

Desmodium incanum was long known as D. canum Schinz & Thellung (= Meibomia cana S. F. Blake) based on the illegitimate Hedysarum canum J. F. Gmelin, a superfluous name for H. racemosum Aublet. The complex nomenclatural history was elaborated by D. H. Nicolson (1978) and L. C. P. Lima et al. (2012, 2014). Hedysarum canescens Miller (1768) is a later homonym of H. canescens Linnaeus (1753), thus illegitimate, and pertains here. Hedysarum canum J. F. Gmelin is a superfluous name for H. racemosum Aublet; Meibomia cana S. F. Blake was intended as a new combination based on that name.

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

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.)

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. 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. 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
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
Synonyms Hedysarum incanum, Aeschynomene incana, D. ancistrocarpum, D. canum, D. frutescens, D. frutescens var. amplyophyllum, D. malacophyllum, D. mauritianum, D. supinum var. amblyophyllum, H. ancistrocarpum, H. malacophyllum, H. mauritianum, H. racemosum, Meibomia adscendens var. incana, M. incana, M. malacophylla, M. supina Hedysarum paniculatum, Meibomia paniculata
Name authority (Swartz) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle: Prodr. 2: 332. (1825) — name conserved (Linnaeus) de Candolle in A. P. de Candolle and A. L. P. P. de Candolle: Prodr. 2: 329. (1825)
Source FNA vol. 11. Treatment author: Hiroyoshi Ohashi. FNA vol. 11. Treatment author: Hiroyoshi Ohashi.
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