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divergent buckwheat, divergent wild buckwheat

St. Catherine's-lace

Habit Herbs, spreading, 1–2(–3) dm, puberulent to short-pilose, greenish to reddish. Shrubs, round to erect, 3–20(–35) × (3–)5–20(–35) dm, tomentose to floccose or glabrate, grayish to reddish.
Stems

aerial flowering stems decumbent to spreading, 0.3–0.5 dm, puberulent to short-pilose.

spreading to erect, occasionally with persistent leaf bases, up to 3/4 or more height of plant, often with a distinct main trunk up to 1 dm thick;

caudex stems absent;

aerial flowering stems erect to spreading, slender to stout, solid, not fistulose, 1–4 dm, tomentose to glabrate.

Leaves

basal and cauline;

basal: petiole 1–4(–5) cm, puberulent to short-pilose, blade elliptic-oblong to orbiculate, 1–2(–2.5) × 1–2(–2.5) cm, puberulent to short-pilose and green on both surfaces;

cauline: petiole (0–)0.1–2 cm, puberulent to short-pilose, absent distally, blades opposite, oblanceolate to oblong or elliptic, 0.3–1(–1.5) × 0.2–0.8(–1.2) cm, similar to basal blade.

cauline, 1 per node;

petiole 0.5–4 cm, tomentose;

blade oblong-ovate to ovate or lanceolate to narrowly oblong, 2.5–7(–10) × 1–5 cm, white-tomentose abaxially, sometimes slightly less so or cinereous to somewhat glabrate and greenish adaxially, margins plane, sometimes crisped.

Inflorescences

cymose, distally uniparous due to suppression of secondary branches, diffuse, 5–25 × 10–45 cm;

branches puberulent;

bracts 1–3(–5) × 1–2 mm.

cymose, open or compact, 5–30 × (2–)5–50(–80) cm;

branches dichotomous, tomentose to floccose or glabrate;

bracts 3, scalelike, broadly triangular, and 1–2 mm, or leaflike, oblanceolate to elliptic, and 5–30 mm.

Peduncles

absent.

absent or erect, slender, 0.1–0.5 cm, tomentose.

Involucres

somewhat appressed to branches, campanulate, 1–2 × 1–2 mm, pilose;

teeth 5, lobelike, spreading to somewhat reflexed, 0.7–1.5 mm.

1 per node, campanulate, 3–5 × 2.5–4 mm, tomentose;

teeth 5, erect, 0.3–0.8 mm.

Flowers

(1–)1.5–2 mm;

perianth yellow, rarely pale yellow, hispidulous and glandular with yellowish-white hairs;

tepals monomorphic, oblong-lanceolate to oblong-ovate;

stamens included, 0.7–1.5 mm;

filaments pilose proximally.

2–4 mm;

perianth white to rose, white-villous abaxially;

tepals connate proximal 1/4, monomorphic, obovate;

stamens exserted, 2–4 mm;

filaments pilose proximally.

Achenes

light brown, 3-gonous, 1.5–2 mm.

brown, 2–3.5 mm, glabrous.

Eriogonum divaricatum

Eriogonum giganteum

Phenology Flowering May–Oct.
Habitat Heavy clay flats and slopes, saltbush, greasewood, and sagebrush communities, pinyon-juniper woodlands
Elevation 1100-2300(-2500) m (3600-7500(-8200) ft)
Distribution
from FNA
AZ; CO; NM; UT; WY
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
Discussion

Eriogonum divaricatum basically is a species of the Colorado Plateau of southwestern Wyoming (Sublette, Sweetwater, and Uinta counties), eastern Utah (Carbon, Emery, Garfield, Grand, Kane, San Juan, Sevier, and Wayne counties), western Colorado (Mesa and Montezuma counties), northern Arizona (Apache, Coconino, and Navajo counties), and northwestern New Mexico (McKinley and San Juan counties), where it is infrequent to common but only rarely abundant. There are several disjunct populations well removed from that core area; the species occurs in Beaver and Millard counties of west-central Utah, and in Clayhole Valley, Mohave County, Arizona. In New Mexico, it was found around San Ysidro, Sandoval County, in 1926. The most extreme disjunctions were two populations found in Argentina during the growing season of 1899–1900. Those plants were named Eriogonum ameghinoi Spegazzini, which ultimately became the only species of the genus Sanmartinia M. Buchinger. Probably introduced there by migrating birds, the species did not persist in South America (J. L. Reveal 1981b).

The divergent wild buckwheat was used ceremonially by the Navajo (Diné) people in one of their snake dances, and portions of the plant were smoked in the treatment of snakebite (A. Clifford, pers. comm.; L. C. Wyman and S. K. Harris 1951).

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

Varieties 3 (3 in the flora).

The California Department of Transportation is planting members of this insular species, especially var. giganteum, on the mainland, where it readily hybridizes with both E. fasciculatum and E. cinereum. Every effort should be made to remove the introduced E. giganteum from coastal California.

The Avalon scrub-hairstreak butterfly (Strymon avalona), which is endemic to Santa Catalina Island, uses Eriogonum giganteum as a food plant.

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

Key
1. Leaf blades oblong-lanceolate to lanceolate; San Clemente Island
var. formosum
1. Leaf blades oblong-ovate to ovate; not San Clemente Island
→ 2
2. Leaf blades 3-7(-10) × 2-5 cm; inflorescences open; Santa Catalina Island
var. giganteum
2. Leaf blades 2.5-3.5(-6) × 1.5-2(-4) cm; inflorescences compact to rarely open; Santa Barbara and Sutil islands
var. compactum
Source FNA vol. 5, p. 429. FNA vol. 5, p. 301.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oregonium Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla
Sibling taxa
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. 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. 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
Subordinate taxa
E. giganteum var. compactum, E. giganteum var. formosum, E. giganteum var. giganteum
Name authority Hooker: Hooker’s J. Bot. Kew Gard. Misc. 5: 265. (1853) S. Watson: Proc. Amer. Acad. Arts 20: 371. (1885)
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