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angle stem buckwheat, angle-stem wild buckwheat

Thurber eriogonum, Thurber's buckwheat, Thurber's wild buckwheat

Habit Herbs, erect to spreading, annual, 1–5(–10) dm, tomen-tose to floccose or glabrous, usually grayish. Herbs, spreading, annual, 0.5–4 dm, glabrate, glabrous or sparsely glandular, greenish, grayish, or reddish.
Stems

caudex absent;

aerial flowering stems erect, striated, angled, solid, not fistulose, 0.5–1 dm, tomentose to floccose.

caudex absent;

aerial flowering stems erect, solid, not fistulose, 0.3–1 dm, often sparsely tomentose and glandular proximally.

Leaves

basal and cauline;

basal: petiole 0.5–3 cm, mostly floccose, blade oblanceolate to oblong-lanceolate, 1–4(–4.5) × (0.2–)0.5–1(–1.3) cm, tomentose abaxially, floccose or glabrate and grayish or greenish adaxially, margins crenulate;

cauline sessile, blade lanceolate to oblong, 0.5–2 × 0.3–0.8 cm, similar to basal blade.

basal;

petiole 1–3 cm;

blade oblong to narrowly ovate, 0.8–4.5 × 0.5–3 cm, densely white-tomentose abaxially, floccose or glabrous and greenish adaxially, margins often crenulate.

Inflorescences

cymose, open, 5–80 × 10–60 cm;

branches striated, angled, sparsely tomentose to glabrate;

bracts 3, scalelike, 1–3 × 1–3 mm.

cymose, mostly diffuse, 5–30 × 5–50 cm;

branches sparsely glandular to glabrate or glabrous;

bracts 3, scalelike, 1–2.5 × 1–2.5 mm.

Peduncles

erect, straight, slender, 1–2 cm, sparsely tomentose to glabrous.

erect, straight, capillary, 0.5–2.5 cm, glabrous and glandular-puberulent distally.

Involucres

turbinate-campanulate to campanulate, 1.5–2.5(–3) × 1.5–2.5(–3), sparsely puberulent;

teeth 5, erect, 0.3–0.6 mm.

broadly turbinate, 1.8–2 × 1.8–2 mm, minutely glandular-puberulent;

teeth 5, erect, 0.4–0.6 mm.

Flowers

1.5–1.8 mm;

perianth white to rose, without a conspicuous rose-purple spot on each outer tepal, minutely glandular-puberulent;

tepals dimorphic, those of outer whorl elliptic to obovate, sometimes inflated proximally, those of inner whorl narrowly spatulate;

stamens exserted, 2–3 mm;

filaments pilose proximally.

1–1.7 mm;

perianth white with greenish or reddish midribs, becoming red, glandular-puberulent with a tuft of long white hairs adaxially;

tepals dimorphic, those of outer whorl broadly pandurate or flabellate, those of inner whorl oblanceolate;

stamens included, 0.7–1.2 mm;

filaments mostly glabrous.

Achenes

light brown to brown, 3-gonous, 1–1.5 mm, glabrous.

brown to black, usually lenticular, 0.6–0.8 mm, glabrous.

2n

= 40.

Eriogonum angulosum

Eriogonum thurberi

Phenology Flowering year-round. Flowering year-round.
Habitat Clayey flats and slopes, mixed grassland, saltbush, and chaparral communities, oak and conifer woodlands Sandy flats, washes, and slopes, saltbush, greasewood, and creosote bush communities, oak, pinyon and/or juniper woodlands, (montane conifer woodlands in Mexico)
Elevation 0-800 m (0-2600 ft) 100-1200 m (300-3900 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NM; Mexico (Baja California, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

The name Eriogonum angulosum has been applied to all of the members of its species complex except E. gossypinum. Since the 1950s, the name consistently has been applied to plants with long, exserted stamens and strongly angled stems of the Inner Coast Ranges (Alameda and Contra Costa counties south), the western foothills of the southern Sierra Nevada (Tulare County south), and the Central Valley (San Joaquin County south). The southern edge of the range is the northern foothills of the Transverse Ranges (Ventura and Los Angeles counties). The species can be common and occasionally abundant but rarely is weedy. A mixed collection (with E. gracillimum) from Barstow, San Bernardino County (K. Brandegee s.n., May 1913, UC), and two sheets of the species from San Diego gathered by Susan Stokes apparently in 1895 (B, SD) are discounted as to location.

In late fruit, the bractlets at the base of the pedicel inside the involucres of Eriogonum angulosum often elongate and broaden into oblanceolate segments that fill the involucre. As a result, the involucre appears to have several rows of teeth. This feature may be seen also in E. viridescens, but typically the involucres there appear to have only two or three rows of teeth. This feature is seen rarely in E. maculatum.

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

Eriogonum thurberi is common to abundant but rarely weedy in northwestern Mexico, southern California (Inyo, Los Angeles, Orange, Riverside, San Bernardino, and San Diego counties), and southern Arizona (Cochise, Gila, Graham, Maricopa, Mohave, Pima, Pinal, Santa Cruz, and Yavapai counties). It just enters New Mexico (Grant County). It and E. thomasii are the annual members of the E. cernuum complex typically found on the Mojave and Sonoran deserts, with E. thurberi extending farther to the east and E. thomasii farther to the north. The two occasionally grow together.

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

Source FNA vol. 5, p. 411. FNA vol. 5, p. 403.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Ganysma Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Ganysma
Sibling taxa
E. abertianum, E. acaule, E. alatum, E. aliquantum, E. allenii, E. alpinum, E. ammophilum, E. ampullaceum, E. androsaceum, E. anemophilum, E. annuum, E. apiculatum, E. apricum, E. arborescens, E. arcuatum, E. aretioides, E. argillosum, E. argophyllum, E. arizonicum, E. artificis, E. atrorubens, E. baileyi, E. batemanii, E. bicolor, E. bifurcatum, E. brachyanthum, E. brachypodum, E. brandegeei, E. breedlovei, E. brevicaule, E. butterworthianum, E. caespitosum, E. capillare, E. cernuum, E. chrysops, E. cinereum, E. cithariforme, E. clavatum, E. clavellatum, E. codium, E. collinum, E. coloradense, E. compositum, E. concinnum, E. congdonii, E. contiguum, E. contortum, E. correllii, E. corymbosum, E. covilleanum, E. crocatum, E. cronquistii, E. crosbyae, E. cusickii, E. darrovii, E. dasyanthemum, E. davidsonii, E. deflexum, E. deserticola, E. desertorum, E. diatomaceum, E. diclinum, E. divaricatum, E. douglasii, E. eastwoodianum, E. effusum, E. elatum, E. elegans, E. elongatum, E. ephedroides, E. eremicola, E. eremicum, E. ericifolium, E. esmeraldense, E. evanidum, E. exaltatum, E. exilifolium, E. fasciculatum, E. flavum, E. fusiforme, E. giganteum, E. gilmanii, E. glandulosum, E. gordonii, E. gossypinum, E. gracile, E. gracilipes, E. gracillimum, E. grande, E. greggii, E. gypsophilum, E. havardii, E. heermannii, E. helichrysoides, E. hemipterum, E. heracleoides, E. hieracifolium, E. hirtellum, E. hirtiflorum, E. hoffmannii, E. holmgrenii, E. hookeri, E. howellianum, E. hylophilum, E. incanum, E. inerme, E. inflatum, E. intrafractum, E. jamesii, E. jonesii, E. kelloggii, E. kennedyi, E. kingii, E. lachnogynum, E. lancifolium, E. latens, E. latifolium, E. lemmonii, E. leptocladon, E. leptophyllum, E. libertini, E. lobbii, E. loganum, E. lonchophyllum, E. longifolium, E. luteolum, E. maculatum, E. mancum, E. marifolium, E. mensicola, E. microthecum, E. mitophyllum, E. mohavense, E. molestum, E. mortonianum, E. multiflorum, E. natum, E. nealleyi, E. nervulosum, E. nidularium, E. niveum, E. nortonii, E. novonudum, E. nudum, E. nummulare, E. nutans, E. ochrocephalum, E. ordii, E. ostlundii, E. ovalifolium, E. palmerianum, E. panamintense, E. panguicense, E. parishii, E. parvifolium, E. pauciflorum, E. pelinophilum, E. pendulum, E. pharnaceoides, E. plumatella, E. polycladon, E. polypodum, E. prattenianum, E. prociduum, E. pulchrum, E. pusillum, E. pyrolifolium, E. racemosum, E. reniforme, E. ripleyi, E. rixfordii, E. robustum, E. rosense, E. roseum, E. rotundifolium, E. rubricaule, E. rupinum, E. salicornioides, E. saxatile, E. scabrellum, E. scopulorum, E. shockleyi, E. siskiyouense, E. smithii, E. soliceps, E. soredium, E. spathulatum, E. spectabile, E. spergulinum, E. sphaerocephalum, E. strictum, E. subreniforme, E. suffruticosum, E. temblorense, E. tenellum, E. ternatum, E. terrenatum, E. thomasii, E. thompsoniae, E. thornei, E. thurberi, E. thymoides, E. tiehmii, E. tomentosum, E. trichopes, E. tripodum, E. truncatum, E. tumulosum, E. twisselmannii, E. umbellatum, E. ursinum, E. vestitum, E. villiflorum, E. vimineum, E. viridescens, E. viridulum, E. viscidulum, E. visheri, E. watsonii, E. wetherillii, E. wootonii, E. wrightii, E. zionis
E. abertianum, E. acaule, E. alatum, E. aliquantum, E. allenii, E. alpinum, E. ammophilum, E. ampullaceum, E. androsaceum, E. anemophilum, E. angulosum, E. annuum, E. apiculatum, E. apricum, E. arborescens, E. arcuatum, E. aretioides, E. argillosum, E. argophyllum, E. arizonicum, E. artificis, E. atrorubens, E. baileyi, E. batemanii, E. bicolor, E. bifurcatum, E. brachyanthum, E. brachypodum, E. brandegeei, E. breedlovei, E. brevicaule, E. butterworthianum, E. caespitosum, E. capillare, E. cernuum, E. chrysops, E. cinereum, E. cithariforme, E. clavatum, E. clavellatum, E. codium, E. collinum, E. coloradense, E. compositum, E. concinnum, E. congdonii, E. contiguum, E. contortum, E. correllii, E. corymbosum, E. covilleanum, E. crocatum, E. cronquistii, E. crosbyae, E. cusickii, E. darrovii, E. dasyanthemum, E. davidsonii, E. deflexum, E. deserticola, E. desertorum, E. diatomaceum, E. diclinum, E. divaricatum, E. douglasii, E. eastwoodianum, E. effusum, E. elatum, E. elegans, E. elongatum, E. ephedroides, E. eremicola, E. eremicum, E. ericifolium, E. esmeraldense, E. evanidum, E. exaltatum, E. exilifolium, E. fasciculatum, E. flavum, E. fusiforme, E. giganteum, E. gilmanii, E. glandulosum, E. gordonii, E. gossypinum, E. gracile, E. gracilipes, E. gracillimum, E. grande, E. greggii, E. gypsophilum, E. havardii, E. heermannii, E. helichrysoides, E. hemipterum, E. heracleoides, E. hieracifolium, E. hirtellum, E. hirtiflorum, E. hoffmannii, E. holmgrenii, E. hookeri, E. howellianum, E. hylophilum, E. incanum, E. inerme, E. inflatum, E. intrafractum, E. jamesii, E. jonesii, E. kelloggii, E. kennedyi, E. kingii, E. lachnogynum, E. lancifolium, E. latens, E. latifolium, E. lemmonii, E. leptocladon, E. leptophyllum, E. libertini, E. lobbii, E. loganum, E. lonchophyllum, E. longifolium, E. luteolum, E. maculatum, E. mancum, E. marifolium, E. mensicola, E. microthecum, E. mitophyllum, E. mohavense, E. molestum, E. mortonianum, E. multiflorum, E. natum, E. nealleyi, E. nervulosum, E. nidularium, E. niveum, E. nortonii, E. novonudum, E. nudum, E. nummulare, E. nutans, E. ochrocephalum, E. ordii, E. ostlundii, E. ovalifolium, E. palmerianum, E. panamintense, E. panguicense, E. parishii, E. parvifolium, E. pauciflorum, E. pelinophilum, E. pendulum, E. pharnaceoides, E. plumatella, E. polycladon, E. polypodum, E. prattenianum, E. prociduum, E. pulchrum, E. pusillum, E. pyrolifolium, E. racemosum, E. reniforme, E. ripleyi, E. rixfordii, E. robustum, E. rosense, E. roseum, E. rotundifolium, E. rubricaule, E. rupinum, E. salicornioides, E. saxatile, E. scabrellum, E. scopulorum, E. shockleyi, E. siskiyouense, E. smithii, E. soliceps, E. soredium, E. spathulatum, E. spectabile, E. spergulinum, E. sphaerocephalum, E. strictum, E. subreniforme, E. suffruticosum, E. temblorense, E. tenellum, E. ternatum, E. terrenatum, E. thomasii, E. thompsoniae, E. thornei, E. thymoides, E. tiehmii, E. tomentosum, E. trichopes, E. tripodum, E. truncatum, E. tumulosum, E. twisselmannii, E. umbellatum, E. ursinum, E. vestitum, E. villiflorum, E. vimineum, E. viridescens, E. viridulum, E. viscidulum, E. visheri, E. watsonii, E. wetherillii, E. wootonii, E. wrightii, E. zionis
Synonyms E. cernuum subsp. thurberi, E. cernuum subsp. viscosum
Name authority Bentham: Trans. Linn. Soc. London 17: 406, plate 18, fig. 1. (1836) Torrey: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 176. (1859)
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