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lambstongue ragwort, western groundsel

arrowleaf groundsel

Habit Herbs perennial or biennial, (1)2–7 dm; caudices button-like, with fleshy, fibrous, unbranched roots. Herbs perennial, (2)5–12(20) dm; caudices branching, woody, rhizomatous.
Stems

1, loosely arachnoid-tomentose, or villous, glabrate with age.

1 or 2–4 and loosely clustered, glabrous or sparsely pubescent.

Leaves

mostly basal;

cauline progressively reduced distally; ± petiolate;

basal and lower cauline elliptic, lanceolate, linear, oblanceolate, rounded-deltate, rarely suborbiculate, bases tapered or truncate to cordate;

margins entire or dentate;

distal becoming sessile and bract-like.

basal present at flowering;

cauline ± evenly distributed along stems, gradually reduced distally, narrowly to widely triangular, bases tapered to truncate or cordate;

margins dentate, rarely subentire;

surfaces sparsely tomentose to nearly glabrous;

proximal petiolate;

distal sessile.

Inflorescences

corymb-like arrays;

bracts 0 or inconspicuous.

corymb- or ± raceme-like arrays;

bracts conspicuous.

Involucres

urn-shaped.

cylindric to narrowly campanulate.

Ray florets

5, rarely 0;

rays 6–15(20) mm, yellow or white to pale yellow.

~8;

rays 9–15 mm.

Disc florets

35–45.

35–45.

Phyllaries

(8)13 or 21;

tips usually black, sometimes green.

(8)13(21), 6–10 mm;

tips green, rarely black.

Calyculi

1–5+, inconspicuous, usually < 2 mm.

2–6 bractlets, inconspicuous, rarely > 2 mm.

Fruits

2.5–3 mm, usually glabrous, sometimes hairy along ribs.

2.5–3.5 mm, glabrous.

Heads

6–15(30+).

10–30(60).

2n

=40, 80.

=40, 80.

Senecio integerrimus

Senecio triangularis

Distribution
[WildflowerSearch map]
[BONAP county map]
[WildflowerSearch map]
[BONAP county map]
Discussion

Western North America. 5 varieties; 3 varieties treated in Flora.

Open areas, rocky streambanks, wet meadows, bogs, damp places in coniferous forests. Flowering May–Sep. 0–2800 m. BR, BW, Casc, CR, ECas, Est, Lava, Sisk, WV. CA, ID, NV, WA; north to AK, northeast to MT, east to WY, southeast to NM. Native.

Some plants with narrow, subentire leaves that taper to the petioles have been found in acidic bogs in Washington and Oregon. A few authors recognize these as variety angustifolia. However, this author has observed several specimens (specifically indicated as being collected in bogs) that had both narrower leaves and the wider leaves more typical of variety triangularis on the same plant.

Source Flora of Oregon, volume 2, page 339
Debra Trock
Flora of Oregon, volume 2, page 341
Debra Trock
Sibling taxa
S. aronicoides, S. crassulus, S. ertterae, S. fremontii, S. hydrophiloides, S. hydrophilus, S. jacobaea, S. serra, S. sphaerocephalus, S. sylvaticus, S. triangularis, S. viscosus, S. vulgaris
S. aronicoides, S. crassulus, S. ertterae, S. fremontii, S. hydrophiloides, S. hydrophilus, S. integerrimus, S. jacobaea, S. serra, S. sphaerocephalus, S. sylvaticus, S. viscosus, S. vulgaris
Subordinate taxa
S. integerrimus var. exaltatus, S. integerrimus var. major, S. integerrimus var. ochroleucus
Synonyms Senecio gibbonsii, Senecio triangularis var. angustifolius, Senecio triangularis var. triangularis
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