| Literature | Crum and Anderson 1981; Flowers 1973; Harthill et al. 1979; Holmberg 1969; Koch 1950a, 1951f; Lawton 1971; McGrew 1976; Shaw 1981c; Showers 1982; Spjut 1971; Strid 1974; Toren 1977. |
| Illustrations | Crum and Anderson 1981; Flowers 1973; Ignatov and Ignatova 2003; Ireland 1982; Lawton 1971; Shaw 1981c. |
| Bioregions | CaR, MP, NW. |
| Vouchers | Modoc Co.: Patterson Lake, South Warner Wilderness, Modoc National Forest, Harpel 2283 (pers. herb.); Siskiyou Co.: upper reaches of Scott Camp Creek Basin, Norris 53072. |
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