Frasera albicaulis |
Frasera albicaulis var. modocensis |
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white-stem elkweed, white-stem frasera |
Modoc frasera |
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Habit | Herbs perennial, 1–6.5 dm. | |||||||||||||||||
Stems | 1–few, with several rosettes. |
densely puberulent. |
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Leaf | blades narrowly white-margined; basal oblanceolate, 4–23 × 0.3–1.2(–2) cm, basal leaves generally longer than lowest internode; cauline leaves opposite, proximal blades oblanceolate to oblong, distal linear-oblong. |
blades abaxially puberulent. |
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Inflorescences | narrow, 1.5–4(–5) cm wide, interrupted proximally, ± continuous distally. |
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Flowers | calyx 3–7(–12) mm; corolla greenish white to pale or medium blue, usually dark blue- to purple-dotted and/or with a dark blue, purple, or green central stripe (except in var. idahoensis), 6–12 mm, lobes oblong-obovate-elliptic, widest near midlength, abruptly tapering to acute to short-acuminate apex; androecial corona scales present, variable among the varieties; style slender, distinct; nectaries and foveae 1 per corolla lobe, foveae distal to nectary, opening into an elliptic-oblong to lance-ovate differentiated area on the corolla surface, rim fringed all around but with fringes shorter distally, or not fringed toward distal end. |
calyx lobes abaxially puberulent; corolla greenish white or pale to medium blue, generally with dark blue to purple spots; corona scales ovate to obovate or oblanceolate, (0.8–)1.5–2.5(–3.3) mm, margins entire or shallowly 2–3-lobed, rarely absent; rim of differentiated area on corolla surface fringed proximally, not fringed toward distal end. |
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2n | = 52 (as Swertia albicaulis var. albicaulis). |
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Frasera albicaulis |
Frasera albicaulis var. modocensis |
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Phenology | Flowering summer. | |||||||||||||||||
Habitat | Dry, brushy sites. | |||||||||||||||||
Elevation | 900–1900 m. (3000–6200 ft.) | |||||||||||||||||
Distribution |
w United States
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CA; NV; OR |
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Discussion | Varieties 5 (5 in the flora). Frasera albicaulis varies in vegetative and abaxial corolla puberulence and in the size and dissection of the androecial corona. It has sometimes been divided into several species and additional varieties, but, from the material available for study at the time of this writing, it appears appropriate to recognize only five varieties, although F. ackermaniae might be considered for inclusion at varietal rank. Each of these varieties has a more or less distinct geographic range, but some intergrade. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Variety modocensis has sometimes been included in var. albicaulis, but var. albicaulis in the narrow sense has been characterized by N. H. Holmgren (1984b) as being more robust than var. modocensis, as well as differing in the corona-scale character noted in the descriptions here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 14. | FNA vol. 14. | ||||||||||||||||
Parent taxa | Gentianaceae > Frasera | Gentianaceae > Frasera > Frasera albicaulis | ||||||||||||||||
Sibling taxa | ||||||||||||||||||
Subordinate taxa | ||||||||||||||||||
Synonyms | Leucocraspedum albicaule, Swertia albicaulis | Swertia modocensis | ||||||||||||||||
Name authority | Grisebach in W. J. Hooker: Fl. Bor.-Amer. 2: 67, plate 154. (1837) | (H. St. John) N. H. Holmgren in A. Cronquist et al.: Intermount. Fl. 4: 22. (1984) | ||||||||||||||||
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