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Frasera albicaulis

white-stem elkweed, white-stem frasera

desert elkweed, desert frasera, white-margined frasera

Habit Herbs perennial, 1–6.5 dm. Herbs perennial, (1–)2–6 dm, glabrous.
Stems

1–few, with several rosettes.

1–few.

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 white-margined;

basal oblanceolate, 2–10 × 0.5–1 cm;

cauline leaves whorled at least proximally on main stem, usually opposite on branches, distal blades linear-lanceolate.

Inflorescences

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

diffuse, often branching at or near base of main stem.

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 (2–)5–12 mm;

corolla greenish white, often purple-dotted, 8–14 mm, lobes elliptic-obovate, apex abruptly acuminate;

androecial corona a fringe, sometimes scarcely developed;

style slender, distinct;

nectaries and foveae 1 per corolla lobe, foveae opening distal to nectary, into a differentiated area on the corolla surface that is proximally oblong with a raised rim fringed ± 1/2 its height, distally wider with rim fringed to base.

Frasera albicaulis

Frasera albomarginata

Distribution
from USDA
w United States
[WildflowerSearch map]
[BONAP county map]
from USDA
w United States
[WildflowerSearch map]
[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.)

Varieties 2 (2 in the flora).

(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
1. Inflorescence branches and calyx lobes glabrous; distal end of differentiated area on corolla lobes cordate to deeply 2-lobed.
var. albomarginata
1. Inflorescence branches and calyx lobes puberulent; distal end of differentiated area on corolla lobes rounded, truncate, or shallowly notched.
var. induta
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. caroliniensis, F. coloradensis, F. fastigiata, F. gypsicola, F. montana, F. neglecta, F. paniculata, F. parryi, F. puberulenta, F. speciosa, F. tubulosa, F. umpquaensis
Subordinate taxa
F. albicaulis var. albicaulis, F. albicaulis var. cusickii, F. albicaulis var. idahoensis, F. albicaulis var. modocensis, F. albicaulis var. nitida
F. albomarginata var. albomarginata, F. albomarginata var. induta
Synonyms Leucocraspedum albicaule, Swertia albicaulis Leucocraspedum albomarginatum, Swertia albomarginata
Name authority Grisebach in W. J. Hooker: Fl. Bor.-Amer. 2: 67, plate 154. (1837) S. Watson: Botany (Fortieth Parallel), 280. (1871)
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