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Davidson buckwheat, Davidson's buckwheat, Davidson's wild buckwheat

ladder buckwheat, ladder wild buckwheat

Habit Herbs, erect, 1–5 dm, glabrous, greenish to grayish. Herbs, erect, annual, (0.5–)3–6(–10) dm, glabrous, glaucous, grayish.
Stems

aerial flowering stems erect, 0.5–1.5(–2) dm, glabrous.

caudex absent;

aerial flowering stems erect, solid, not fistulose, (0.5–)1–2 dm, glabrous.

Leaves

basal;

petiole 1–5 cm, floccose;

blade round to reniform, (0.3–)1–2(–4) × (0.3–)1–2(–4) cm, densely white-tomentose abaxially, floccose to glabrate and mostly greenish adaxially.

basal;

petiole 1–10 cm, tomentose;

blade sub-cordate to orbiculate, (1.5–)2–5(–8) × (1.5–)2–5(–8) cm, densely white-tomentose abaxially, floccose to subglabrous and green adaxially, margins often wavy.

Inflorescences

cymose, occasionally distally uniparous due to suppression of secondary branches, open, 5–40 × 5–35 cm;

branches straight or nearly so, infrequently inwardly curved distally, glabrous;

bracts 1–3 × 1–2 mm.

cymose, spreading when immature, quickly becoming narrowly erect and strict with whiplike branches, (5–)10–50(–80) × 10–50 cm;

branches glabrous, glaucous;

bracts 3, scalelike, 1–1.5(–2) × 0.4–1 mm.

Peduncles

absent.

absent or erect, straight, slender, 0.1–0.2 cm, glabrous.

Involucres

appressed to branches, cylindric-turbinate, 3–4 × 2–2.5 mm, glabrous;

teeth 5, erect, 0.2–0.3 mm.

turbinate, 2–2.5(–3) × 1.5–2.5 mm, glabrous;

teeth 5, erect, 0.5–1.5 mm.

Flowers

1.5–2 mm;

perianth white to pink or red, rarely yellow, glabrous;

tepals monomorphic, oblong-obovate;

stamens included, 1–1.5 mm;

filaments pilose proximally.

1.5–2 mm;

perianth white with green or reddish midribs, becoming pinkish, glabrous;

tepals dimorphic, those of outer whorl oblong, those of inner whorl lanceolate;

stamens exserted, 1.5–2.5 mm;

filaments pilose proximally.

Achenes

brown, 3-gonous, 2 mm.

dark brown to blackish, 3-gonous, 2–2.5 mm, glabrous.

2n

= 40.

= 40.

Eriogonum davidsonii

Eriogonum exaltatum

Phenology Flowering May–Sep. Flowering May–Oct.
Habitat Sandy to gravelly flats and slopes, mixed grassland, saltbush, chaparral, and sagebrush communities, oak and montane conifer woodlands Sandy to gravelly flats and slopes, saltbush, creosote bush, greasewood, blackbrush, and mesquite communities, rarely in pinyon-juniper woodlands
Elevation (400-)900-2600 m ((1300-)3000-8500 ft) 500-1400 m (1600-4600 ft)
Distribution
from FNA
AZ; CA; NV; UT; Mexico (Baja California)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NV; UT
[BONAP county map]
Discussion

Eriogonum davidsonii is widespread and mostly common to occasionally abundant or weedy in Arizona, California, southern Nevada, and southern Utah. It is exceedingly variable. In the northern part of California, its range approaches that of E. luteolum var. luteolum, and the two can be difficult to differentiate. To the south, in Tulare County, the distinction between E. davidsonii and E. luteolum var. pedunculatum also is difficult. Specimens of Eriogonum davidsonii with curved inflorescence branches resemble E. cithariforme in the mountains of southern California, and care must be taken to separate E. davidsonii from its more robust relative, E. molestum in the San Jacinto Mountains of Riverside County. The disjunct populations in Utah and Arizona are somewhat different in appearance but presently do not seem worthy of taxonomic separation. The epithet juncinellum is available should recognition be desired.

Seeds of Davidson’s wild buckwheat were pounded into a meal and eaten dry by the Kawaiisu people of southern California (M. L. Zigmond 1981).

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

Eriogonum insigne has been a troublesome taxon.  The type, collected by E. Palmer in 1876, is a curious specimen from near Paragonah in Iron County, Utah.  That expression has not been recollected and, after another frustrating review of the type material, it is now referred to E. deflexum, along with other odd specimens from southern Nevada and California that have always been difficult to assign.  As a result, the tall, upright plants with long, whiplike branches of northwestern Arizona (Mohave County), southern Nevada (northeastern Clark and southern Lincoln counties), and southwestern Utah (southwestern Washington County), are now recognized under the name E. exaltatum.  Some specimens remain problematic.  Immature plants of E. exaltatum (Goodding 2302, GH, MIN, MO, NY, RM, UC) resemble E. bifurcatum. Specimens from Eureka Valley (DeDecker 4741, NY) and western Pahrump Valley (Abrams 14248, DS, GH, NY) in Inyo County, California, appear to belong to E. exaltatum.

Like Eriogonum exaltatum, some populations of E. deflexum var. deflexum have nearly erect involucres.  The plants from the Buried Hills (Nye and Clark counties, Nevada) are particularly odd.  Single plants from a few collections in Kane County, Utah, have sessile, seemingly erect involucres in the forks of inflorescence branches.  None of these plants has the characteristic long, whiplike branches of E. exaltatum, and they are not included in E. deflexum var. deflexum. The type of E. deflexum var. rectum from San Bernardino County, California (Reveal & Broome 6385, CAS, NY, US, etc.), has individual specimens with both deflexed and somewhat erect involucres, along with whiplike branches.  Collections from Imperial and San Diego counties, previously associated with what is here termed E. exaltatum, are now considered specimens of E. deflexum.  Clearly, more work is required to understand these species fully.

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

Source FNA vol. 5, p. 422. FNA vol. 5, p. 397.
Parent taxa Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oregonium 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. 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. 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. 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
Synonyms E. molestum var. davidsonii, E. vimineum var. davidsonii, E. vimineum var. glabrum, E. vimineum subsp. juncinellum
Name authority Greene: Pittonia 2: 295. (1892) M. E. Jones: Contr. W. Bot. 15: 61. (1929)
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