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flat top buckwheat, yucca buckwheat, yucca wild buckwheat

Thorne's buckwheat, Thorne's wild buckwheat

Habit Shrubs, erect, not scapose, 3–10(–12) × 3–6(–8) dm, tomentose or glabrous, grayish or greenish. Subshrubs, spreading and matted, not scapose, 0.4–0.8 × 0.4–1(–2.5) dm.
Stems

erect, without persistent leaf bases, up to 1/2 or more height of plant;

caudex stems absent;

aerial flowering stems erect, slender, solid, not fistulose, 0.5–2 dm, tomentose or glabrous.

spreading, with persistent leaf bases, up to 1/4 height of plant;

caudex stems compact;

aerial flowering stems spreading, slender, solid, not fistulose, 0.1–0.2 dm, floccose to slightly tomentose.

Leaves

basal and cauline, 1 per node;

petiole 0.1–0.5 cm, mostly tomentose;

blade oblanceolate, 0.6–1.5 × 0.2–0.3 cm, tomentose on both surfaces, occasionally slightly less so adaxially, margins plane.

cauline, 1 per node or fasciculate;

petiole 0.01–0.02 cm, tomentose;

blade linear, 0.4–0.6 × 0.05–0.1 cm, densely white-tomentose adaxially, finely villous and green adaxially, margins revolute.

Inflorescences

cymose, flat-topped and in tiers, 15–40 × 15–40 cm;

branches dichotomous, divaricately arranged in a zig-zag pattern, tomentose or glabrous;

bracts 3, scalelike, 1–7 mm.

umbellate-cymose, compact, 0.5–1 × 0.5–1 cm;

branches usually dichotomous, otherwise with secondaries suppressed, glabrous or nearly so;

bracts 3, scalelike, linear, 0.5–1 mm.

Peduncles

absent.

absent.

Involucres

1 per node, turbinate, 2–2.5 × 1.5–2 mm, glabrous;

teeth 5, erect, 0.4–0.6 mm.

1 per node, turbinate, 1.5–2 × 1–1.5 mm, floccose;

teeth 5, erect, 0.4–0.6 mm.

Flowers

2–2.5 mm;

perianth white to pale yellow, glabrous;

tepals connate proximal 1/4 dimorphic, those of outer whorl obovate, those of inner whorl oblong;

stamens exserted, 2–4 mm;

filaments pilose proximally.

1.5–2 mm;

perianth white, glabrous;

tepals connate proximal 1/4, dimorphic, those of outer whorl obovate, 1–1.5 mm wide, those of inner whorl oblanceolate, 0.8–1 mm wide, connate proximally;

stamens slightly exserted, 2–3 mm;

filaments pilose proximally.

Achenes

light brown to brown, 2.5–3 mm, glabrous.

light brown, 2–2.5 mm, glabrous except for papillate beak.

Eriogonum plumatella

Eriogonum thornei

Phenology Flowering Apr–Oct. Flowering May–Jul.
Habitat Sandy flats, washes, and slopes, mixed grassland, saltbush, blackbrush, and creosote bush communities, oak and pinyon-juniper woodlands Copper-rich quartzite gravel on ridges, pinyon woodlands
Elevation 400-1700 m (1300-5600 ft) 1800 m (5900 ft)
Distribution
from FNA
AZ; CA; NV
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Eriogonum plumatella is encountered infrequently, primarily on the Mojave Desert, where it occurs in two forms, one with pubescent (var. plumatella) and one with glabrous (var. jaegeri) inflorescence branches. As both forms occur occasionally in the same population, the varieties are not considered to be taxonomically significant. Eriogonum plumatella occurs from Kern County, California, south through Los Angeles (including the foothills of the San Gabriel Mountains), San Bernardino, and Riverside counties to eastern San Diego County. To the east the species is found in Clark County, Nevada, and Mohave and western Yavapai counties, Arizona. A single specimen (Palmer s.n., GH) reportedly was gathered in Utah. Repeated efforts to find the plant in Washington County, Utah, have been unsuccessful, and the record is discounted here.

This species is the food plant for the rare pallid dotted-blue butterfly (Euphilotes pallescens pallescens). According to M. L. Zigmond (1981), the Kawaiisu pounded the seeds into a powder and made a mush. Given the small size of the achenes, and the paucity of large populations, the task of gathering sufficient seed must have been daunting. In taste, these seeds differ little from other, more common members of wild buckwheat, so it is likely that achenes of several species were gathered and processed into a watery meal.

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

Eriogonum thornei is known from a single canyon area in the New York Mountains, San Bernardino County. Shultz elevated Thorne’s wild buckwheat to species status when she proposed E. phoeniceum, here considered a variety of E. microthecum. Eriogonum thornei and E. ericifolium are weakly differentiated, with minimal morphologic differences, and yet they occur on different substrates and are well-removed biogeographically from each other. Thorne’s wild buckwheat is a protected plant in California.

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

Source FNA vol. 5, p. 308. FNA vol. 5, p. 255.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Eucycla 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. 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. 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. 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
Synonyms E. plumatella var. jaegeri E. ericifolium var. thornei, E. ericifolium subsp. thornei
Name authority Durand & Hilgard: J. Acad. Nat. Sci. Philadelphia, n. s. 3: 45. (1855) (Reveal & Henrickson) L. M. Shultz: Harvard Pap. Bot. 3: 51. (1998)
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