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Frasera albicaulis

white-stem elkweed, white-stem frasera

Umpqua frasera, Umpqua frasera or green-gentian, Umpqua green-gentian

Habit Herbs perennial, 1–6.5 dm. Herbs monocarpic, 3–14 dm, glabrous.
Stems

1–few, with several rosettes.

1.

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 not white-margined;

basal spatulate-obovate, 15–60 (including proximal petiolar portions) × 3–17 cm;

cauline leaves generally whorled, blade widely elliptic to ovate, apex obtuse to acute (proximal) to acuminate (distal).

Inflorescences

narrow, 1.5–4(–5) cm wide, interrupted proximally, ± continuous distally.

dense, sometimes interrupted proximally.

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 7–15 mm;

corolla white or pale greenish yellow, pale yellow near midvein, sometimes with violet-blue tinge, not spotted, 5.3–11 mm, lobes ovate-oblong, apex acuminate;

androecial corona a dense fringe to 5 mm;

style short, ± stout and indistinctly differentiated from summit of ovary;

nectaries and foveae 1 per corolla lobe, foveae round or nearly so, opening directly adaxial to nectary, without a differentiated area on the corolla surface, rim raised, with long, incurved fringes all around.

2n

 = 78.

Frasera albicaulis

Frasera umpquaensis

Phenology Flowering late spring–summer.
Habitat Mountain meadows, open woods.
Elevation 1200–2000 m. (3900–6600 ft.)
Distribution
from USDA
w United States
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[BONAP county map]
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.)

Former uncertainty as to the distinctness of Frasera umpquaensis from F. fastigiata has been cleared up by B. L. Wilson et al. (2010).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key
1. Stems and abaxial or both leaf surfaces puberu­lent; rim of differentiated area on corolla surface not fringed at distal end.
→ 2
2. Corona scales oblong, margins lacerate or deeply toothed, ultimate divisions threadlike.
var. albicaulis
2. Corona scales ovate to obovate or oblan­ceolate, margins entire or shallowly 2–3-lobed, rarely absent.
var. modocensis
1. Stems glabrous; leaf blades glabrous or puberulent only near base and abaxially along midvein; rim of differentiated area on corolla surface fringed all around, fringes shorter near distal end.
→ 3
3. Corona scales ovate to elliptic, margins entire or shallowly undulate-erose or toothed.
var. cusickii
3. Corona scales ovate to elliptic to oblong-lanceolate, margins lacerate or deeply lobed.
→ 4
4. Corollas greenish white or pale to medium blue, generally with dark blue to purple spots; corona scales 1–4 mm, oblong-lanceolate.
var. nitida
4. Corollas pale blue, usually without darker spots; corona scales 2–6 mm, widely ovate to elliptic.
var. idahoensis
Source FNA vol. 14. FNA vol. 14.
Parent taxa Gentianaceae > Frasera Gentianaceae > Frasera
Sibling taxa
F. ackermaniae, F. albomarginata, F. caroliniensis, F. coloradensis, F. fastigiata, F. gypsicola, F. montana, F. neglecta, F. paniculata, F. parryi, F. puberulenta, F. speciosa, F. tubulosa, F. umpquaensis
F. ackermaniae, F. albicaulis, F. albomarginata, F. caroliniensis, F. coloradensis, F. fastigiata, F. gypsicola, F. montana, F. neglecta, F. paniculata, F. parryi, F. puberulenta, F. speciosa, F. tubulosa
Subordinate taxa
F. albicaulis var. albicaulis, F. albicaulis var. cusickii, F. albicaulis var. idahoensis, F. albicaulis var. modocensis, F. albicaulis var. nitida
Synonyms Leucocraspedum albicaule, Swertia albicaulis Swertia umpquaensis
Name authority Grisebach in W. J. Hooker: Fl. Bor.-Amer. 2: 67, plate 154. (1837) M. Peck & Applegate: Madroño 6: 12. (1941)
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