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arrow-leaf clover

elongated clover, productive clover, Shasta clover

Habit Herbs annual, 15–70 cm, glabrous. Herbs perennial, 15–45 cm, glabrous.
Stems

erect or ascending, branched.

± erect, loosely cespitose, branched.

Leaves

palmate;

stipules linear-lanceolate, 1–3.5 cm, margins entire, apex subulate or setaceous;

petiole 0.5–10 cm;

petiolules 1 mm;

leaflet 3, blades obovate to oblong, elliptic or lanceolate, 0.5–4 × 0.5–1.5 cm, base cuneate, veins prominent, thickened, margins spinulose-denticulate, apex apiculate, surfaces glabrous.

basal and cauline, palmate;

stipules ovate-lanceolate, 0.5–2 cm, margins usually entire, sometimes lobed, apex acute to acuminate;

petiole 0.5–12 cm;

petiolules 1 mm;

leaflets 3, blades lanceolate or elliptic, 0.5–2 × 0.3–1.3 cm, base cuneate, veins prominent, margins serrate, apex acute, apiculate, surfaces glabrous.

Inflorescences

terminal or axillary, 50–100+-flowered, globose, ovoid, or oblong, 3–6 × 2–3.5 cm;

involucres absent.

terminal or axillary, 15–30-flowered, ellipsoid or conic, 1.5–2 × 1–3 cm, rachis prolonged beyond flowers, undivided or forked, often bearing sterile flower buds distally;

involucres absent.

Peduncles

1–12 cm.

2–13 cm, slightly twisted apically.

Pedicels

absent;

bracteoles lanceolate, 6–7 mm, acuminate.

strongly reflexed in fruit, 0.5 mm;

bracteoles minute, lanceolate.

Flowers

12–16 mm;

calyx urceolate, not bilabiate, inflated in fruit, 6–10 mm, glabrous, veins 20–36, connected by transverse veins in fruit, tube 3–5 mm, lobes reflexed, subequal, subulate, as long as tube, orifice constricted;

corolla white becoming pink, 12–15 mm, banner ovate, broadly clawed, striate, 12–15 × 2–4 mm, apex acute-acuminate.

12–14 mm;

calyx pink to purple, campanulate, 3–3.5 mm, glabrous, veins 10 (5 sometimes faint), tube 1.5–1.7 mm, lobes subequal, triangular-subulate, orifice open;

corolla pink to deep purple, 12–14 mm, banner oblong, 12–14 × 4–5 mm, apex rounded or retuse.

Legumes

ellipsoid, 2.5–2.5 mm, shorter than calyx.

obliquely ellipsoid, 5 mm.

Seeds

2 or 3, brown, ovoid, 1–1.5 mm, roughened.

1 or 2, brown, often purple-mottled, flattened ovoid, 2–3 mm, smooth.

2n

= 16.

= 16.

Trifolium vesiculosum

Trifolium productum

Phenology Flowering Apr–Jul. Flowering May–Sep.
Habitat Fields, roadsides, forest openings. Open coniferous woods, rocky places, stream banks, grassy meadows, near springs.
Elevation 0–1000 m. (0–3300 ft.) 1100–2800 m. (3600–9200 ft.)
Distribution
from FNA
AL; AR; CA; FL; GA; LA; MA; MO; MS; OK; OR; SC; TX; VA; WA; s Europe; e Europe; w Asia [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; NV; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Trifolium vesiculosum was first introduced into cultivation in the United States in 1963 and is grown in southern and western states (J. D. Miller and H. D. Wells 1985).

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

Trifolium productum is morphologically most similar to T. kingii, from which it differs by its glabrous calyces and inflorescence rachises surpassing the flowers to 1.5 cm and apically forked (M. Zohary and D. Heller 1984). Trifolium productum is geographically isolated from T. kingii; the former is restricted to northern California, western Oregon, and western Nevada, while the latter is restricted to Utah and easternmost Nevada (J. M. Gillett 1972).

(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
T. albopurpureum, T. alexandrinum, T. amoenum, T. amphianthum, T. andersonii, T. andinum, T. angustifolium, T. appendiculatum, T. arvense, T. attenuatum, T. aureum, T. barbigerum, T. barnebyi, T. beckwithii, T. bejariense, T. bifidum, T. bolanderi, T. brandegeei, T. breweri, T. buckwestiorum, T. calcaricum, T. campestre, T. carolinianum, T. cernuum, T. ciliolatum, T. columbinum, T. cyathiferum, T. dasyphyllum, T. dedeckerae, T. depauperatum, T. dichotomum, T. douglasii, T. dubium, T. echinatum, T. eriocephalum, T. fragiferum, T. friscanum, T. fucatum, T. glomeratum, T. gracilentum, T. grayi, T. gymnocarpon, T. haydenii, T. hirtum, T. howellii, T. hybridum, T. hydrophilum, T. incarnatum, T. jokerstii, T. kentuckiense, T. kingii, T. lappaceum, T. latifolium, T. leibergii, T. lemmonii, T. longipes, T. lupinaster, T. macilentum, T. macraei, T. macrocephalum, T. medium, T. microcephalum, T. microdon, T. monanthum, T. mucronatum, T. nanum, T. nigrescens, T. obtusiflorum, T. oliganthum, T. ornithopodioides, T. owyheense, T. palmeri, T. parryi, T. pinetorum, T. piorkowskii, T. plumosum, T. polyodon, T. pratense, T. productum, T. reflexum, T. repens, T. resupinatum, T. retusum, T. rollinsii, T. siskiyouense, T. sonorense, T. stoloniferum, T. striatum, T. subterraneum, T. suffocatum, T. thompsonii, T. tomentosum, T. trichocalyx, T. variegatum, T. virginicum, T. willdenovii, T. wormskioldii
T. albopurpureum, T. alexandrinum, T. amoenum, T. amphianthum, T. andersonii, T. andinum, T. angustifolium, T. appendiculatum, T. arvense, T. attenuatum, T. aureum, T. barbigerum, T. barnebyi, T. beckwithii, T. bejariense, T. bifidum, T. bolanderi, T. brandegeei, T. breweri, T. buckwestiorum, T. calcaricum, T. campestre, T. carolinianum, T. cernuum, T. ciliolatum, T. columbinum, T. cyathiferum, T. dasyphyllum, T. dedeckerae, T. depauperatum, T. dichotomum, T. douglasii, T. dubium, T. echinatum, T. eriocephalum, T. fragiferum, T. friscanum, T. fucatum, T. glomeratum, T. gracilentum, T. grayi, T. gymnocarpon, T. haydenii, T. hirtum, T. howellii, T. hybridum, T. hydrophilum, T. incarnatum, T. jokerstii, T. kentuckiense, T. kingii, T. lappaceum, T. latifolium, T. leibergii, T. lemmonii, T. longipes, T. lupinaster, T. macilentum, T. macraei, T. macrocephalum, T. medium, T. microcephalum, T. microdon, T. monanthum, T. mucronatum, T. nanum, T. nigrescens, T. obtusiflorum, T. oliganthum, T. ornithopodioides, T. owyheense, T. palmeri, T. parryi, T. pinetorum, T. piorkowskii, T. plumosum, T. polyodon, T. pratense, T. reflexum, T. repens, T. resupinatum, T. retusum, T. rollinsii, T. siskiyouense, T. sonorense, T. stoloniferum, T. striatum, T. subterraneum, T. suffocatum, T. thompsonii, T. tomentosum, T. trichocalyx, T. variegatum, T. vesiculosum, T. virginicum, T. willdenovii, T. wormskioldii
Synonyms T. kingii subsp. productum, T. kingii var. productum
Name authority Savi: Fl. Pis. 2: 165. (1798) — (as vessiculosum) Greene: Erythea 2: 181. (1894)
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