Eriogonum incanum |
Eriogonum inflatum |
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frosted buckwheat, frosted wild buckwheat |
bottle stopper, desert trumpet, Indian pipeweed |
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Habit | Herbs, matted, dioecious, 0.5–3 × 1–4 dm wide, tomentose to floccose. | Herbs, erect, perennial, occasionally flowering first year, 1–10(–15) dm, glabrous, usually glaucous, grayish. |
Stems | caudex spreading; aerial flowering stems erect or nearly so, slender, solid, not fistulose, arising at nodes of caudex branches and at distal nodes of short, nonflowering aerial branches, 0.1–2(–2.5) dm, tomentose to floccose. |
caudex compact; aerial flowering stems erect, solid or hollow and fistulose, (0.2–)2–5 dm, glabrous, usually glaucous, occasionally hirsute proximally. |
Leaves | in loose to congested basal rosettes; petiole (0.3–)0.5–1 cm, tomentose; blade oblong to oblong-ovate or spatulate, 0.5–1.5 × 0.3–0.7 cm, densely white- or grayish-tomentose on both surfaces, sometimes greenish adaxially, margins entire, plane. |
basal; petiole 2–6 cm, hirsute; blade oblong-ovate to oblong or rounded to reniform, (0.5–)1–2.5(–3) × (0.5–)1–2(–2.5) cm, short-hirsute and grayish or greenish on both surfaces, sometimes less so or glabrous and green adaxially, margins occasionally undulate. |
Inflorescences | capitate and 0.5–2 cm wide, mature pistillate plants open and umbellate, 1–3 × 1–4 cm; branches tomentose to floccose; bracts 2–6, leaflike, 0.1–0.5 × 0.1–0.3 cm, often absent immediately below involucre. |
cymose, open, spreading to erect, 5–70 × 5–50 cm; branches occasionally fistulose, glabrous, usually glaucous; bracts 3, scalelike, 1–2.5(–5) × 1–2.5 mm. |
Peduncles | erect, straight, filiform to capillary, 0.5–2(–3.5) cm, glabrous. |
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Involucres | 1 per node but occasionally appearing congested, turbinate-campanulate, 2.5–3 × 2–2.5 mm, tomentose; teeth 5–8, erect, 0.5–1 mm. |
turbinate, 1–1.5 × 1–1.8 mm, glabrous; teeth 5, erect, 0.4–0.6 mm. |
Flowers | stipelike base 0.5–1 mm; perianth yellow, glabrous; staminate flowers 2–3 mm, tepals ovate; pistillate flowers 4–6 mm, tepals oblanceolate, often becoming reddish in fruit; stamens exserted, 2–3 mm; filaments pilose proximally. |
(1–)2–3(–4) mm; perianth yellow with greenish or reddish midribs, densely hirsute with coarse curved hairs; tepals monomorphic, narrowly ovoid to ovate; stamens exserted, 1.3–2.5 mm; filaments glabrous or sparsely pubescent proximally. |
Achenes | light brown to brown, 3–3.5 mm, glabrous except for sparsely pubescent beak. |
light brown to brown, lenticular to 3-gonous, 2–2.5 mm, glabrous. |
2n | = 32. |
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Eriogonum incanum |
Eriogonum inflatum |
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Phenology | Flowering Jun–Sep. | Flowering year-round. |
Habitat | Sandy to gravelly or rocky granitic or occasionally volcanic flats, slopes, and outcrops, mixed grassland, manzanita, and sagebrush communities, montane conifer woodlands | Sandy to gravelly washes, flats, and slopes, mixed grassland, saltbush, creosote bush, mesquite, and sagebrush communities, pinyon and/or juniper woodlands |
Elevation | (1900-) 2100-4000 m ((6200-) 6900-13100 ft) | -30-1800(-2000) m (-100-5900(-6600) ft) |
Distribution |
CA; NV
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AZ; CA; CO; NM; NV; UT; Mexico (Baja California, Sonora)
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Discussion | Eriogonum incanum is common throughout the central and southern Sierra Nevada of California (Alpine, El Dorado, Fresno, Inyo, Madera, Mariposa, Nevada, Tulare, and Tuolumne counties) and extreme west-central Nevada (Carson City, Douglas, and Washoe counties). It is a food plant for the green hairstreak butterfly (Callophrys lemberti), the Pacific dotted-blue (Euphilotes enoptes), and the gorgon copper (Gaeides gorgon). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The cause of the fistulose stem and inflorescence branches in Eriogonum inflatum was imaginatively attributed by A. M. Stone and C. T. Mason (1979) to the larvae of gall insects. This fallacy continues to appear in the literature. Greenhouse studies have shown that stems of this and some other species of the genus inflate without the presence of any insects. Other researchers have shown that the inflation involves a build-up of CO2 within the stems, which take over as the primary photosynthetic body as leaves wilt or eventually dry up and fall away from the plant (C. D. Osmond et al. 1987). Not all individuals of E. inflatum will have fistulose stems and branches, as this feature is partly a function of available moisture: the drier the conditions, the less pronounced the inflation. Stems produced in the summer tend to be inflated less frequently than those produced in the spring. The “annual” phase of Eriogonum inflatum is distinct from its truly annual relatives. Its flowering stems and inflorescence branches are distinctly grayish, whereas those of the true annuals are green or yellowish green. As circumscribed here, Eriogonum inflatum occurs in Arizona, southern and east-central California, western Colorado, northwestern New Mexico, central and southern Nevada, and southern and eastern Utah. Some Native Americans occasionally ate newly emerged stems of Eriogonum inflatum (S. A. Weber and P. D. Seaman 1985; M. L. Zigmond 1981). The hollow stems were used as drinking tubes (Weber and Seaman) and pipes (E. W. Gifford 1936). This wild buckwheat is a food plant for the desert metalmark butterfly (Apodemia mormo deserti). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 5, p. 366. | FNA vol. 5, p. 386. |
Parent taxa | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Oligogonum | Polygonaceae > subfam. Eriogonoideae > Eriogonum > subg. Ganysma |
Sibling taxa | ||
Synonyms | E. marifolium var. incanum, E. ursinum var. rosulatum | E. glaucum, E. inflatum var. deflatum, E. trichopes subsp. glaucum |
Name authority | Torrey & A. Gray: Proc. Amer. Acad. Arts 8: 161. (1870) | Torrey & Frémont: in J. C. Frémont, Rep. Exped. Rocky Mts., 317. (1845) |
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