Polyctenium fremontii (S. Watson) Greene, Leafl. Bot. Observ. Crit. 2: 219. 1912; Smelowskia fremontii S. Watson, Proc. Amer. Acad. Arts 11: 123. 1876. TYPE: United States, Oregon, “Hills around Lake Klamath, 4 May 1846, J. C. Fremont 384 (lectotype designated by Rollins (1838a: 304), GH!; isolectotypes, K!, NY!, US!).
Braya pectinata Greene, Erythea 3: 69. 1895. TYPE: United States, California, Modoc Co., Ewing Creek, May 1894, Mrs. R. M. Austin s.n. (holotype, NDG; isotype, UC!).
Polyctenium bisulcatum Greene, Leafl. Bot. Observ. Crit. 2: 220. 1912; P. fremontii var. bisulcatum (Greene) Rollins, Rhodora 40: 304. 1938; Smelowskia fremontii var. bisulcata (Greene) O. E. Schulz in Engler, Pflanzenreich IV. 105(Heft 86): 359. 1924. TYPE: United States, Oregon, Grant Co., Silvies Valley, Blue Mts., 24 May 1885, T. Howell s.n. (holotype, US!; isotypes, GH!, NY!, OSC).
Polyctenium fremontii var. confertum Rollins, Harvard Pap. Bot. 1(4): 47. 1993. TYPE: United States, California, Mono Co., drying areas at the edge of Larkin Lake, NE end of Trench Canyon, Bodie Hills, 6750 ft, 12 Jul 1983, A. Tiehm & M. Lavin 8118 (holotype, GH!; isotypes, CAS!, NY!).
Plyctenium glabellum Greene, Leafl. Bot. Observ. Crit. 2: 210. 1912; S. fremontii var. glabella (Greene) O. E. Schulz in Engler, Pflazenreich IV. 105(Heft 86): 359. 1924. TYPE: United States, Oregon, Malheur Co., along streams, flats near head of Dry Creek, 1100 m, 27 May 1896, J. B. Leiberg 2147 (holotype, US!; isotypes, NY!; ORE).
Polyctenium williamsiae Rollins, J. Arnold Arbor. 64: 508. 1983. TYPE: United States, Nevada, Washoe Co., edge of vernal pond, foothills of the Virginia Range, E of Little Washoe Lake, 5680 ft, 10 Jun 1982, A. Tiehm & M. Williams 7135 (holotype, GH!; isotypes, CAS!, K!, NY!, POM!).
Herbs, perennial, cespitose, woody at base, sparsely to densely pubescent. Stems (2–)5–16(–20) cm, few to numerous from base, branched above, sparsely to densely pubescent below, sometime glabrous and glaucous above. Leaves pectinate, rigid, (0.5–)1–2.2(–2.8) cm, often persisting in subsequent seasons as pectinate spines; petiole 0–3(–5) mm, winged, nearly absent in uppermost leaves; leaf lobes (2–)3–4(–5) per side, linear, with a prominent midvein and a narrow band of blade, sparsely to densely pubescent with dendritic trichomes, often with simple or forked trichomes along margin and apex; terminal lobe (2–)4–7(–10) x (0.3–)0.5–1(–1.5) mm, as long as or slightly longer that adjacent lateral lobes. Racemes compact or greatly elongated in fruit; fruiting pedicels divaricate-ascending, (2–)4–7(–10) mm, slender, sparsely pubescent or glabrous. Sepals 1.5–2 x 0.9–1.1 mm, glabrous or sparsely pubescent, hyaline margined; petals white or purplish, obovate to oblanceolate, 3–4 x 1.5–2 mm, attenuate to base; filaments 1.2–2 mm; anthers ovate, 0.4–0.5 mm. Fruit linear to oblong, rarely ovate-oblong, (2–)4–13(–18) x 0.9–2 mm, angustiseptate, erect to ascending; style (0.2–)0.4–0.7(–1) mm. Seeds brown, oblong, 0.7–0.9 x 0.3–0.5 mm.
Habitat: mud flats, dry meadows, sagebrush areas, edge of vernal pools, shallow soil on basalt, dry stream beds and swales, gravel bars, rocky wash.
Elevation: 1000–2650 m.
Distribution: United States (California, Idaho, Nevada, Oregon).
Notes: Very highly variable in fruit size and the compactness of the fruiting raceme, both of which were highly used in splitting the species in several taxa. For further discussion on this variation, see my account of the genus in the Flora of North America, vol. 7).