Frasera albicaulis
Frasera coloradensis
white-stem elkweed, white-stem frasera
Colorado frasera
1–few, with several rosettes.
1–several.
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 narrowly white-margined;
basal narrowly oblanceolate, 4–17 × 0.4–2 cm;
cauline leaves opposite, distal blades linear-oblanceolate.
narrow, 1.5–4(–5) cm wide, interrupted proximally, ± continuous distally.
diffuse, 5–30 cm wide, branching near base of main stems.
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 7–13 mm;
corolla white to cream, usually rather sparsely purple-dotted, 7–10 mm, lobes oblong-obovate, apex abruptly acuminate;
androecial corona poorly developed, usually comprising erose scales 0.2–1 mm and few trichomes;
style slender, distinct;
nectaries and foveae 1 per corolla lobe, foveae opening distal to nectary, into an orbiculate to elliptic-oblong differentiated area on the corolla lobe, rim ± fringed all around.
Frasera albicaulis
Frasera coloradensis
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.)
Frasera coloradensis is endemic to Baca, Bent, Las Animas, and Prowers counties in southeastern Colorado and Cherokee County in adjacent Oklahoma.
To a greater degree than other Frasera species, F. coloradensis forms relatively large clusters of divergent rather than erect stems. Otherwise, it is somewhat similar to F. puberulenta, from which it is separated by about 1500 km. Frasera coloradensis has corymboid inflorescences, about as wide as long, with branches or pedicels arising in pairs at each node of the main axis, and many long leaves in the inflorescences; F. puberulenta has more elongate inflorescences, usually with branches and/or pedicels arising in whorls from some nodes of the main axis, and few if any large leaves in the inflorescences. In F. puberulenta the nectary is more deeply pocketed. Frasera coloradensis is also somewhat similar to F. albomarginata var. induta. It differs in its opposite rather than proximally whorled leaves, its larger leaves within the inflorescence, and the highly dissimilar shape of the differentiated areas on the corolla lobes.
Frasera coloradensis is in the Center for Plant Conservation’s National Collection of Endangered Plants.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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 |
CA
OR
WA
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
