Senecio triangularis
Senecio integerrimus
arrow-leaf groundsel, arrow-leaf ragwort, arrowleaf butterweed, groundsel
lambstongue ragwort, mountain butterweed, one-stem butterweed, tall western groundsel, western groundsel
glabrous or sparsely floccose-tomentose when young.
arachnose, loosely tomentose, or villous (hairs crisped, jointed), glabrescent.
single or loosely clustered.
single.
evenly distributed; petiolate;
blades narrowly triangular, (3–)4–10+ × 2–6 cm, bases usually ± truncate, sometimes tapered, margins usually dentate, rarely subentire (distal leaves subsessile, smaller).
progressively reduced distally; ± petiolate;
blades elliptic, lanceolate, linear, oblanceolate, rounded-deltate, or suborbiculate, 6–25 × 1–6 cm, bases ± tapered or truncate to cordate, margins entire or ± dentate (distal leaves sessile, bractlike).
± 8;
corolla laminae 9–15 mm.
usually ± 8 or ± 13, sometimes 0;
corolla laminae 6–15(–20) mm (usually yellow, ochroleucous to white in one variety).
(± 8) ± 13 (± 21), 6–10 mm, tips usually green, rarely black.
usually ± 13 or ± 21, rarely ± 8, (4–)5–12(–15) mm, tips usually black, sometimes green.
of 2–6 bractlets (rarely more than 2 mm).
of 1–5+ linear to filiform bractlets (seldom more than 2 mm).
10–30(–60) in corymbiform to subracemiform arrays.
6–20(–40+) in corymbiform arrays (peduncle of terminal head often shorter than others).
glabrous.
usually glabrous, sometimes hirtellous (mostly on angles).
= 40, 80.
= 40, 80.
Senecio triangularis
Senecio integerrimus
Plants of Senecio triangularis with narrow, subentire leaves that taper to the petioles are occasionally encountered in acid bogs in Oregon and Washington and less frequently elsewhere. They are regarded as edaphic variants; they have been recognized as var. angustifolius.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Varieties 5 (5 in the flora).
The varieties of Senecio integerrimus are distinguished by morphology and geography.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Basal leaves with distinct petioles, blades usually ovate to rounded-deltate, sometimes obovate to oblanceolate; ray corollas white or ochroleucous | var. ochroleucus |
1. Basal leaves with or without distinct petioles, blades elliptic, lanceolate, oblanceolate, rounded-deltate, sublinear, or suborbiculate; ray corollas yellow (or rays 0) | → 2 |
2. Herbage glabrous or glabrate at flowering (except in leaf axils and among heads); phyllaries linear-subulate, tips usually green, minutely (if at all) black | var. integerrimus |
2. Herbage usually arachnose, tomentose, or villous at flowering; phyllaries lanceolate to linear-subulate, tips black (if minutely so, then narrowly lanceolate and broader than subulate) | → 3 |
3. Basal and proximal leaves oblong or lanceolate to sublinear; heads 3–6(–16+); phyllaries 10–15+ mm | var. scribneri |
3. Basal and proximal leaves mostly elliptic to oblanceolate, sometimes elliptic or rounded-deltate to suborbiculate; heads usually 6–15(–30+; if fewer than 6, leaves lanceolate or broader); phyllaries 5–12 mm. | → 4 |
4. Plants copiously arachnose, tomentose, or villous at flowering; phyllaries linear-subulate, 8–12 mm, tips minutely, if at all, blackened | var. major |
4. Plants copiously to sparsely arachnose, tomentose, or villous at flowering; phyllaries mostly lanceolate (seldom as narrow as linear-subulate), 5–10 mm, tips black | var. exaltatus |
SW CO Wildflowers- Local floras:
BC, 
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
KS Wildflowers, 
MN Wildflowers, 
PNW Herbaria, Turner Photog. 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
