Trifolium campestre |
Trifolium sonorense |
|
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field clover, hop clover, hop trefoil, low hop-clover, pinnate hop clover |
Sonoran clover |
|
Habit | Herbs annual, 5–40 cm, slightly villous or glabrous. | Herbs perennial, 25–38+ cm, pubescent. |
Stems | erect to ascending, branched. |
prostrate, branched. |
Leaves | pinnate; stipules ovate-lanceolate, 0.5–0.8 cm, margins entire, glandular, apex acuminate; petiole 0.3–2 cm; lateral leaflet petiolules 0.5–0.6 mm, terminal leaflet stalk 3–5 mm; leaflets 3, blades rhombic to obovate, 0.4–1.5 × 0.4–0.8 cm, base cuneate, lateral veins prominent, ± parallel, ascending, margins denticulate distally, apex truncate or retuse, surfaces strigose adaxially. |
palmate; stipules narrowly triangular, 0.7–1.7 cm, margins entire or finely serrulate, apex usually acute or acuminate, sometimes 2-fid; petiole 0.3–5 cm; petiolules to 1 mm; leaflets 3, blades obovate to obcordate, 0.9–1.6 × 0.7–1.2 cm, base cuneate, veins moderately thickened, margins serrate to weakly so, apex rounded or emarginate, mucronulate, surfaces slightly hairy abaxially, glabrous adaxially. |
Inflorescences | axillary, 30–60-flowered, globose or broadly ovoid, 0.8–1.5 × 0.7–1 cm; involucres absent. |
axillary, 10–20-flowered, depressed-globose or globose, 0.8–1.6 × 0.9–1.6 cm, rachis prolonged beyond flowers; involucres a narrow rim, or slightly proximally connate bracteoles of proximal flowers, 0.1–0.5 mm. |
Peduncles | 1.5–3.5 cm. |
2.8–5 cm. |
Pedicels | reflexed, 0.7–1.2 mm; bracteoles a fringe of red setae. |
reflexed in fruit, 1–3 mm; bracteoles linear-triangular, 0.5 mm. |
Flowers | 4.3–5 mm; calyx campanulate, strongly bilabiate, 1.3–1.5 mm, glabrous, veins 5, tube 0.3–0.6 mm, lobes unequal, adaxial deltate, very short, lateral and abaxial linear-subulate, each tipped with 1 or 2 stiff hairs, orifice open; corolla yellow becoming brown, 3.5–6 mm, ribbed, banner persistent, obovate, enveloping other petals, boat-shaped, 4.3–5 × 2.8–3.2 mm, apex broad, acute. |
5.7–6.7 mm; calyx tubular, 3.3–6.5 mm, pubescent, veins 10, tube 0.8–1 mm, lobes subequal, narrowly triangular, orifice open; corolla white or pink, 5.3–6.5 mm, banner obovate, 5.3–6.5 × 2.8–3.8 mm, apex broadly rounded or broadly acute. |
Legumes | stipitate, oblong, 2–2.5 mm. |
obovoid, 4.3–4.4 mm. |
Seeds | 1 or 2, yellow, ellipsoid, 1–1.5 mm, smooth, lustrous. |
2, brownish orange or olive-brown, globose or broadly reniform, 1.2–1.7 mm, smooth. |
2n | = 14. |
= 16. |
Trifolium campestre |
Trifolium sonorense |
|
Phenology | Flowering Jun–Aug. | Flowering Aug–Oct. |
Habitat | Roadsides, fields. | Dry stream banks, grassy places. |
Elevation | 0–1700 m. (0–5600 ft.) | 1500–1800 m. (4900–5900 ft.) |
Distribution |
AK; AL; AR; AZ; CA; CT; DC; DE; FL; GA; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SC; TN; TX; VA; VT; WA; WI; WV; WY; BC; NB; NF; NS; ON; PE; QC; SPM; Europe; w Asia; n Africa [Introduced in North America; introduced also in South America, e Asia (China), s Africa, Pacific Islands (Hawaii, New Zealand), Australia]
|
AZ; Mexico (Chihuahua, Jalisco, Sinaloa, Sonora) |
Discussion | Trifolium filiforme Linnaeus and T. procumbens Linnaeus are rejected names that were used historically for T. campestre (J. E. Dandy 1958; N. J. Turland et al. 1996). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Trifolium sonorense has long been equated with T. amabile Kunth, from which T. K. Ahlquist (2012) and also Ahlquist & M. A. Vincent have shown it to be distinct by longer sepal lobes (more than 3 mm), keel petal claws (more than 1.7 mm), and filament tubes (more than 3.6 mm). Trifolium sonorense is known from western Mexico and southernmost Arizona (Cochise County), largely in the Sonoran Desert region, and in mountainous Jalisco. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 11. | FNA vol. 11. |
Parent taxa | Fabaceae > subfam. Faboideae > Trifolium | Fabaceae > subfam. Faboideae > Trifolium |
Sibling taxa | ||
Synonyms | Chrysaspis campestris | |
Name authority | Schreber in G. F. Hoffmann: Deutschl. Fl. 4: 16, plate 253. (1804) | T. K. Ahlquist & Vincent: Phytoneuron 2018-1: 1, fig. 1. (2018) |
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