Eriogonum

Heartleaf buckwheat Eriogonum compositum, copyright Mount Rainier National Park.

Belongs within: Polygonaceae.

Eriogonum spergulinum, the spurry buckwheat
Published 23 June 2022

Wandering around sandy highlands of the southwest United States, you may encounter a sparse, wiry weed growing between five and forty centimetres in height. This is the spurry buckwheat Eriogonum spergulinum.

Spurry buckwheat Eriogonum spergulinum, copyright Dcrjsr.

Members of the buckwheat family Polygonaceae are found worldwide but tend to be easily overlooked as low, scrubby weeds. In North America, one of the most diverse genera is Eriogonum, known from about 250 species though many are difficult to readily distinguish (Hickman 1993). Eriogonum spergulinum is one of the more recognisable species in the genus. As mentioned above, it grows in sandy soils, particularly those dominated by worn-down granite, and is found at altitudes between 1200 and 3500 metres. It is an annual herb with basal leaves of a linear shape, less than two millimetres wide but up to thirty millimetres long. The greater part of the plant’s height is made up by the slender, cyme-like inflorescence bearing unribbed, four-toothed involucres on slender stalks. The flowers are up to three millimetres in diameter with a white perianth marked by darker stripes. Overall, E. spergulinum in flower resembles a drifting cloud of small white stars.

Close-up on Eriogonum spergulinum flowers, copyright Tom Hilton.

Three varieties of Eriogonum spergulinum have been recognised though they are not always distinct and tend to intergrade with each other. In most parts of the species’ range, plants belong to the variety E. spergulinum var. reddingianum. This variety is characterised by erect inflorescences with glandular axes and flowers about two millimetres in diameter. The other two varieties are both restricted to the Sierra Nevada mountains of California. Eriogonum spergulinum var spergulinum resembles var. reddingianum but produces larger flowers, about three millimetres in diameter. Eriogonum spergulinum var. pratense is more distinctive. Inflorescences are prostrate to ascending, only about two to five millimetres in height, and lack glands on the axes. Flowers are only 1.5 millimetres across. Pratense is also a higher-altitude variety, found at heights above 2500 metres. The Sierra Nevada varieties are both uncommon; if any variety is likely to be found, it is the widespread reddingianum.

Systematics of Eriogonum
<==Eriogonum
|--E. alpinumH93
|--E. ampullaceumH93
|--E. (subg. Ganysma) angelense Moran 1969M69
|--E. angulosumH93
|--E. apiculatumH93
|--E. apricumH93
| |--E. a. var. apricumH93
| `--E. a var. prostratumH93
|--E. arborescensH93
|--E. argillosumH93
|--E. baileyiH93
| |--E. b. var. baileyiH93
| `--E. b. var. prraebens [incl. E. baileyi var. divaricatum]H93
|--E. beatleyaeH93
|--E. bifurcatumH93
|--E. brachyanthumH93
|--E. brachypodumH93
|--E. breedloveiH93
| |--E. b. var. breedloveiH93
| `--E. b. var. shevockiiH93
|--E. butterworthianumH93
|--E. cernuumH93
| |--E. c. var. cernuumH93
| `--E. c. var. viminaleH93
|--E. cespitosumH93
|--E. cinereumH93
|--E. cithariforme [=E. gracile var. cithariforme; incl. E. cithariforme var. agninum, E. gracile var. polygonoides]H93
|--E. compositumH93
|--E. congdonii [=E. ternatum var. congdonii]H93
|--E. contiguumH93
|--E. covilleanumH93
|--E. crocatumH93
|--E. dasyanthemumH93
|--E. davidsonii [=E. molestum var. davidsonii]H93
|--E. deflexumH93
| |--E. d. var. deflexumH93
| |--E. d. var. baratumH93
| |--E. d. var. nevadenseH93
| `--E. d. var. rectumH93
|--E. deserticolaH93
|--E. diclinumH93
|--E. douglasiiH93
|--E. eastwoodianumH93
|--E. elatumH93
| |--E. e. var. elatumH93
| `--E. e. var. villosumH93
|--E. elegansH93
|--E. elongatumH93
|--E. eremicolaH93
|--E. ericifoliumH93
| |--E. e. var. ericifoliumH93
| `--E. e. var. thorneiH93
|--E. esmeraldenseH93
|--E. fasciculatumRJ11
| |--E. f. var. fasciculatumH93
| |--E. f. var. flavoviridumH93
| |--E. f. var. foliolosumH93
| `--E. f. var. polifoliumH93
|--E. foliosum [incl. E. foliosum var. hastatum]H93
|--E. giganteumH93
| |--E. g. var. giganteumH93
| |--E. g. var. compactumH93
| `--E. g. var. formosumH93
|--E. gilmaniiH93
|--E. glandulosum [incl. E. carneum]H93
|--E. gossypinumH93
|--E. gracileH93
| |--E. g. var. gracileH93
| `--E. g. var. incultumH93
|--E. gracilipesH93
|--E. gracillimumH93
|--E. grande [=E. latifolium ssp. grande]H93
| |--E. g. var. grandeH93
| |--E. g. var. rubescensH93
| `--E. g. var. timorumH93
|--E. heermanniiH93
| |--E. h. var. heermanniiH93
| |--E. h. var. argenseH93
| |--E. h. var. floccosumH93
| |--E. h. var. humiliusH93
| |--E. h. var. occidentaleH93
| `--E. h. var. sulcatumH93
|--E. heracleoidesH93
|--E. hirtellumH93
|--E. hirtiflorumH93
|--E. hoffmanniiH93
| |--E. h. var. hoffmanniiH93
| `--E. h. var. robustiusH93
|--E. hookeriH93
|--E. incanumH93
|--E. inermeH93
|--E. inflatumH93
| |--E. i. var. inflatumH93
| `--E. i. var. deflatumH93
|--E. (subg. Clastomyelon) intrafractumH93
|--E. kelloggiiH93
|--E. kennedyiH93
| |--E. k. var. kennedyiH93
| |--E. k. var. alpigenumH93
| |--E. k. var. austromontanumH93
| |--E. k. var. pinicolaH93
| `--E. k. var. purpusiiH93
|--E. latensH93
|--E. latifolium [incl. E. oblongifolium]H93
|--E. libertiniH93
|--E. lobbiiH93
|--E. luteolumH93
| |--E. l. var. luteolum [incl. E. luteolum var. pedunculatum, E. luteolum var. saltuarium]H93
| `--E. l. var. caninumH93
|--E. maculatumH93
|--E. marifoliumH93
|--E. microthecumH93
| |--E. m. var. microthecumH93
| |--E. m. var. alpinum non E. alpinumH93
| |--E. m. var. ambiguumH93
| |--E. m. var. corymbosoidesH93
| |--E. m. var. johnstoniiH93
| |--E. m. var. lapidicolaH93
| |--E. m. var. laxiflorumH93
| |--E. m. var. panamintense non E. panamintenseH93
| `--E. m. var. simpsoniiH93
|--E. mohavenseH93
|--E. molleM69
|--E. nervulosumH93
|--E. nidulariumH93
|--E. nortoniiH93
|--E. nudumH93
| |--E. n. var. nudumH93
| |--E. n. var. auriculatumH93
| |--E. n. var. decurrensH93
| |--E. n. var. deductumH93
| |--E. n. var. indictumH93
| |--E. n. var. murinumH93
| |--E. n. var. oblongifolium non E. oblongifoliumH93
| |--E. n. var. paralinumH93
| |--E. n. var. pauciflorumH93
| |--E. n. var. pubiflorumH93
| |--E. n. var. regirivumH93
| |--E. n. var. scapigerumH93
| `--E. n. var. westoniiH93
|--E. nummulare [incl. E. kearneyi, E. kearneyi var. monoense]H93
|--E. nutans [incl. E. nutans var. glabrum]H93
|--E. ochrocephalumH93
| |--E. o. var. ochrocephalumH93
| `--E. o. var. alexanderaeH93
|--E. ordiiH93
|--E. ovalifoliumH93
| |--E. o. var. ovalifoliumH93
| |--E. o. var. eximiumH93
| |--E. o. var. nivaleH93
| |--E. o. var. purpureumH93
| `--E. o. var. vineumH93
|--E. palmerianumH93
|--E. panamintense [incl. E. panamintense var. mensicola, E. rupinum]H93
|--E. parishiiH93
|--E. parvifolium [incl. E. parvifolium var. lucidum, E. parvifolium var. paynei]H93
|--E. pendulumH93
|--E. plumatella [incl. E. plumatella var. jaegeri]H93
|--E. polycladonBT72
|--E. polypodumH93
|--E. prattenianumH93
| |--E. p. var. prattenianumH93
| `--E. p. var. aviumH93
|--E. prociduumH93
|--E. puberulumH93
|--E. pusillumH93
|--E. pyrolifoliumH93
|--E. reniformeH93
|--E. rixfordiiH93
|--E. rosenseH93
|--E. roseumH93
|--E. saxatileH93
|--E. sericeumJ23
|--E. shockleyiH93
|--E. siskiyouenseH93
|--E. spergulinumH93
| |--E. s. var. spergulinumH93
| |--E. s. var. pratenseH93
| `--E. s. var. reddingianumH93
|--E. sphaerocephalumH93
| |--E. s. var. sphaerocephalumH93
| `--E. s. var. halimioidesH93
|--E. strictumH93
| |--E. s. var. strictumH93
| |--E. s. var. anserinumH93
| |--E. s. var. greeneiH93
| `--E. s. var. proliferumH93
|--E. temblorenseH93
|--E. ternatumH93
|--E. thomasiiH93
|--E. thurberiH93
|--E. tomentosumCS90
|--E. trichopesH93
| |--E. t. var. trichopesH93
| `--E. t. var. hooveriH93
|--E. tripodumH93
|--E. truncatumH93
|--E. twisselmanniiH93
|--E. umbellatumH93
| |--E. u. var. umbellatumH93
| |--E. u. var. bahiiformeH93
| |--E. u. var. chlorothamnusH93
| |--E. u. var. covilleiH93
| |--E. u. var. dichrocephalumH93
| |--E. u. var. furcosumH93
| |--E. u. var. glaberrimumH93
| |--E. u. var. hausknechtiiH93
| |--E. u. var. humistratumH93
| |--E. u. var. juniporinumH93
| |--E. u. var. minusH93
| |--E. u. var. munziiH93
| |--E. u. var. nevadense non E. deflexum var. nevadenseH93
| |--E. u. var. polyanthum [incl. E. umbellatum var. goodmanii]H93
| |--E. u. var. speciosumH93
| |--E. u. var. subaridumH93
| |--E. u. var. torreyanumH93
| `--E. u. var. versicolorH93
|--E. ursinumH93
|--E. vestitumH93
|--E. vimineumH93
|--E. viridescensH93
|--E. wrightiiBT72
| |--E. w. var. wrightiiH93
| |--E. w. var. membranaceumH93
| |--E. w. var. nodosumH93
| |--E. w. var. olanchenseH93
| |--E. w. var. subscaposumH93
| `--E. w. var. trachygonumH93
`--E. zapoatoense Moran 1969M69

*Type species of generic name indicated

References

[BT72] Baker, E. W., & D. M. Tuttle. 1972. New species and further notes on the Tetranychoidea mostly from the southwestern United States (Acarina: Tetranychidae and Tenuipalpidae). Smithsonian Contributions to Zoology 116: 1–37.

[CS90] Corey, D. T., & I. J. Stout. 1990. Ground surface arachnids in sandhill communities of Florida. Journal of Arachnology 18: 167–172.

[H93] Hickman, J. C. (ed.) 1993. The Jepson Manual: Higher Plants of California. University of California Press: Berkeley (California).

[J23] James, E. 1823. Account of an Expedition from Pittsburgh to the Rocky Mountains, performed in the years 1819 and ’20, by order of the Hon. J. C. Calhoun, sec’y of war: under the command of Major Stephen H. Long. From the notes of Major Long, Mr. T. Say, and other gentlemen of the exploring party vol. 1. H. C. Carey & I. Lea: Philadelphia.

[M69] Moran, R. 1969. Twelve new dicots from Baja California, Mexico. Transactions of the San Diego Society of Natural History 15 (17): 265–295.

[RJ11] Rising, J. D., A. Jaramillo, J. L. Copete, P. G. Ryan & S. C. Madge. 2011. Family Emberizidae (buntings and New World sparrows). In: Hoyo, J. del, A. Elliott & D. A. Christie (eds) Handbook of the Birds of the World vol. 16. Tanagers to New World Blackbirds pp. 428–683. Lynx Edicions: Barcelona.

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