Senecio triangularis
Senecio serra
arrow-leaf groundsel, arrow-leaf ragwort, arrowleaf butterweed, groundsel
butterweed groundsel, sawtooth groundsel, serrated ragwort, tall butterweed, tall ragwort
glabrous or sparsely floccose-tomentose when young.
glabrous or lightly floccose-tomentose proximally when young.
single or loosely clustered.
single or loosely clustered.
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).
evenly distributed (proximal often withering before flowering); petiolate or subsessile;
blades lanceolate or narrowly lanceolate to sublinear, 5–15(–20+) × (1–)1.5–4 cm, bases tapered, margins dentate to subentire (distal leaves smaller, bractlike).
± 8;
corolla laminae 9–15 mm.
± 5 or ± 8;
corolla laminae 5–10 mm.
(± 8) ± 13 (± 21), 6–10 mm, tips usually green, rarely black.
± 8 or ca. 13, 4–9 mm, tips usually green, sometimes black.
of 2–6 bractlets (rarely more than 2 mm).
of 2–6 linear to filiform bractlets (0.5–5 mm).
10–30(–60) in corymbiform to subracemiform arrays.
30–90+ in corymbiform to subpaniculiform arrays.
glabrous.
glabrous or glabrate.
= 40, 80.
= 40.
Senecio triangularis
Senecio serra
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 2 (2 in the flora).
Varieties of Senecio serra are distinguished by head size and distribution.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Heads 40–90+; phyllaries ± 8, 4–6 mm; ray florets ± 5, corolla laminae 5–7 mm; disc florets 10–20 | var. serra |
1. Heads (12–)30–50; phyllaries ± 13, 7–9 mm; ray florets ± 8, corolla laminae 7–10 mm; disc florets 20–40+ | var. admirabilis |
BC
CA
OR
WA
Flora NW
PNW Herbaria
SW CO Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
