Eriogonum rotundifolium |
Eriogonum exaltatum |
|
---|---|---|
round-leaf wild buckwheat, roundleaf buckwheat |
ladder buckwheat, ladder wild buckwheat |
|
Habit | Herbs, spreading, annual, 0.5–4 dm, glabrous and often glaucous, greenish to grayish. | Herbs, erect, annual, (0.5–)3–6(–10) dm, glabrous, glaucous, grayish. |
Stems | caudex absent; aerial flowering stems erect, solid, not fistulose, 0.1–0.5(–0.7) dm, glabrous. |
caudex absent; aerial flowering stems erect, solid, not fistulose, (0.5–)1–2 dm, glabrous. |
Leaves | basal; petiole 1.5–4 cm, floccose; blade cordate to orbiculate, 1–2(–3) × 1–2.5(–3) cm, densely white-tomentose abaxially, floccose or subglabrous and greenish adaxially, margins plane. |
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, open to diffuse, usually flat-topped, 5–35 × 5–35 cm; branches glabrous; bracts 3, scalelike, 1–2.5 × 0.5–2 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 | erect, straight, stoutish, 0.3–1.5 cm, glabrous. |
absent or erect, straight, slender, 0.1–0.2 cm, glabrous. |
Involucres | turbinate to campanulate, 1–2 × 1.5–2.5 mm, glabrous; teeth 5, erect, 0.4–0.8 mm. |
turbinate, 2–2.5(–3) × 1.5–2.5 mm, glabrous; teeth 5, erect, 0.5–1.5 mm. |
Flowers | 1–2.5 mm; perianth white to pink with greenish to reddish midribs, becoming rose to red, glabrous; tepals dimorphic, those of outer whorl flabellate, those of inner whorl lanceolate; stamens included, 1.2–1.7 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 | dark brown, 3-gonous, 1.5–2 mm, glabrous. |
dark brown to blackish, 3-gonous, 2–2.5 mm, glabrous. |
2n | = 40. |
= 40. |
Eriogonum rotundifolium |
Eriogonum exaltatum |
|
Phenology | Flowering May–Oct. | Flowering May–Oct. |
Habitat | Sandy to gravelly flats and slopes, mixed grassland, saltbush, creosote bush, and mesquite communities, juniper woodlands | Sandy to gravelly flats and slopes, saltbush, creosote bush, greasewood, blackbrush, and mesquite communities, rarely in pinyon-juniper woodlands |
Elevation | 600-1800 m (2000-5900 ft) | 500-1400 m (1600-4600 ft) |
Distribution |
AZ; NM; TX; Mexico (Chihuahua, Coahuila)
|
AZ; CA; NV; UT |
Discussion | Eriogonum rotundifolium is the southern counterpart to E. cernuum, being common to abundant and occasionally even weedy. Its overall range, however, is significantly smaller. It occurs in Arizona only in Cochise County, but is found more widely in New Mexico, and is common in the trans-Pecos region of western Texas, with scattered populations in Dimmit, Ector, Foard, and Knox counties outside that region. A sterile Edwin James specimen gathered in 1820 (NY) supposedly was collected near the Rocky Mountains and may be Eriogonum rotundifolium. Also seen at NY is an unattributed, redistributed collection of this species labeled only “Colorado.” Until better documented material from that state is seen, the species is considered not to be a member of the Colorado flora. F. A. Elmore (1943) reported that the round-leaf wild buckwheat was used by the Navajo (Diné) people as an emetic. My own consumption of a few seeds, as a self-experiment, produced no particular urge to vomit. Inasmuch as the treatment was taken after swallowing ants, it is difficult to know whether the ants or the seeds were the emetic. G. M. Hocking (1956) reported that the leaves were used for sore throats and the stems were eaten raw (the latter proving in the same self-experiment not to be particularly tasty, leaving a slightly sour aftertaste). Hocking also reported that the roots were used medicinally but mentioned no specific ailment. (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. 402. | FNA vol. 5, p. 397. |
Parent taxa | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Ganysma | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Ganysma |
Sibling taxa | ||
Synonyms | E. cernuum subsp. glaucescens, E. cernuum subsp. rotundifolium, E. rotundifolium var. angustius | |
Name authority | Bentham: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 14: 21. (1856) | M. E. Jones: Contr. W. Bot. 15: 61. (1929) |
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