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big-head clover, large-head clover

balloon sack clover, cowbag clover, dwarf sack clover, poverty clover

Habit Herbs perennial, 5–25 cm, villous. Herbs annual, 1–30 cm, glabrous.
Stems

erect or ascending, branched.

erect or decumbent, branched.

Leaves

palmate;

stipules ovate, obovate, or oblong, 1–3 cm, margins entire, irregularly lobed, or serrate, apex acute or acuminate;

petiole 1–14 cm;

petiolules 0.9–1.2 mm;

leaflets (5–)7–9, blades broadly to narrowly obovate, often folded, 1–2.7 × 0.4–1.1 cm, base cuneate, veins thickened, especially distally, margins serrulate, apex rounded or truncate, apiculate, surfaces villous abaxially, sparsely villous to glabrate adaxially.

palmate;

stipules sheathing proximally, ovate-oblong to lanceolate, 0.4–1.3 cm, margins entire or serrulate, apex short triangular-cuspidate;

petiole 1–5 cm;

petiolules to 1 mm;

leaflets 3, blades lanceolate, linear, obovate, or oblanceolate, 0.4–2.5 × 0.1–0.7 cm, base cuneate, veins moderately thickened abaxially, margins entire, serrate, or pinnately lobed, apex rounded, truncate, acute, or retuse, surfaces glabrous.

Inflorescences

terminal, 20–32-flowered, globose or ovoid-ellipsoid, 2.5–8 × 3–7 cm;

involucres absent.

axillary or terminal, 3–15-flowered, globose or depressed-globose, 0.5–1.5 × 0.5–1.5 cm;

involucres flattened, 3–13 mm, ± distinct or incised 1/2 their length, lobes 5–7, linear to elliptic or irregular, or vestigial, reduced to narrow ring, apex rounded to broad and irregularly erose, not split.

Peduncles

2–8 cm.

2–6 cm.

Pedicels

erect, 1–1.5 mm;

bracteoles broadly ovate, membranous, to 0.5 mm, truncate.

straight, 0–0.5 mm;

bracteoles absent.

Flowers

20–30 mm;

calyx campanulate, 10–22 mm, villous, veins 10–15, tube 2.5–4 mm, lobes subequal, subulate, plumose, orifice open;

corolla white, creamy white, or pinkish, keel petals deep pink, 20–28 mm, banner ovate or oblong, 20–28 × 10–13 mm, apex rounded or slightly emarginate.

3–10 mm;

calyx campanulate, 2–5 mm, glabrous, veins 5, tube 1–2.5 mm, lobes unequal, triangular-lanceolate or subulate, orifice open;

corolla white or pink, 3–11 mm, inflated in fruit, banner broadly ovate, 4–7 × 3–8 mm, apex rounded, broad, acute, or retuse.

Legumes

ovoid, 4–5 mm.

sessile or stipitate, ovoid, obovoid, or oblong, 2–4 mm.

Seeds

1 or 2, yellow or reddish, mitten-shaped to ellipsoid, 2.5–3 mm, smooth.

1–6, gray or tan, mottled, mitten-shaped, 1.2–1.6 mm, irregularly bumpy.

2n

= 32, 48.

= 16.

Trifolium macrocephalum

Trifolium depauperatum

Phenology Flowering Apr–Jun.
Habitat Rocky places, hard, compacted clay-gumbo, lava beds, sage-covered slopes, full sun.
Elevation 80–2500 m. (300–8200 ft.)
Distribution
from FNA
CA; ID; NV; OR; WA
[WildflowerSearch map]
[BONAP county map]
from USDA
w North America; nw Mexico; c North America; South America (Chile, Peru)
[WildflowerSearch map]
[BONAP county map]
Discussion

Trifolium macrocephalum has the largest inflorescences of any clover. Trifolium megacephalum Nuttall (1818) is an illegitimate replacement name for Lupinaster macrocephalum Pursh.

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

Varieties 3 (3 in the flora).

The three varieties of Trifolium depauperatum are relatively easily distinguished by characteristics of the involucres and fruit stipes. Leaf morphology is not helpful in making the distinctions; in each variety, leaf margins can range from nearly entire or toothed or laciniate. In the phylogenetic treatment by N. W. Ellison et al. (2006), T. depauperatum is not allied with T. fucatum and other clovers with inflated corollas but rather with T. obtusiflorum, T. trichocalyx, and T. willdenovii (although with weak support).

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

Key
1. Involucres reduced to narrow vestigial ring; inflorescences 1–1.5 cm diam.; flowers 7–10 mm; legumes ovoid, 3–4 mm, sessile.
var. depauperatum
1. Involucres with evident bracts; inflorescences 0.5–1 cm diam.; flowers 3–8 mm; legumes oblong, ovoid, or obovoid, 2–4 mm, sessile or stipes 0.5–1 mm.
→ 2
2. Involucral lobes broad, irregular, with broad, hyaline margins and reticulate veins; legumes oblong, 3–4 mm, ± sessile.
var. amplectens
2. Involucral lobes oblong, often with narrow hyaline margins and raised, parallel veins; legumes ovoid or obovoid, 2–3 mm, stipes 0.5–1 mm.
var. truncatum
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. 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. vesiculosum, 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. 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. vesiculosum, T. virginicum, T. willdenovii, T. wormskioldii
Subordinate taxa
T. depauperatum var. amplectens, T. depauperatum var. depauperatum, T. depauperatum var. truncatum
Synonyms Lupinaster macrocephalum Lupinaster depauperatus
Name authority (Pursh) Poiret in J. Lamarck et al.: Encycl., suppl. 5: 336. (1817) Desvaux: J. Bot. Agric. 4: 69, plate 32, fig. 2. (1814)
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