Senecio hydrophiloides

Rydberg

Mem. New York Bot. Gard. 1: 441. 1900.

Endemic
Synonyms: Senecio foetidus Howell Senecio foetidus var. hydrophiloides (Rydberg) T. M. Barkley ex Cronquist Senecio oreganus
Treatment appears in FNA Volume 20. Treatment on page 558. Mentioned on page 547.

Perennials (biennials?), 30–100 (–140) cm (caudices erect, roots fleshy-fibrous). Herbage usually glabrous or glabrescent (young plants sparsely tomentose). Stems usually single, sometimes 2–4 clustered (sometimes reddish-tinged). Leaves progressively reduced distally; usually petiolate (petioles often winged); blades elliptic to broadly lanceolate, 5–15 (–20) × 2–7 cm, bases broadly to narrowly tapered, margins dentate to denticulate (distal leaves sessile, bractlike). Heads (6–) 15–30+ in congested or loose, corymbiform arrays. Calyculi of 2–5 bractlets (less than 2 mm). Phyllaries (± 8) ± 13 (± 21), 4–9 mm, tips (minutely to prominently) black. Ray-florets 0 or (± 3 or 5) ± 8; corolla laminae 5–10 mm. Cypselae glabrous. 2n = 40.


Phenology: Flowering spring–early summer.
Habitat: Damp hillsides, non-alkaline meadows, seepage sites
Elevation: 1200–2200 m

Distribution

V20-1237-distribution-map.gif

Alta., B.C., Calif., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.

Discussion

Plants of Senecio hydrophiloides from toward the western end of the range tend to have the heads more or less congested and eradiate and stems loosely clustered; plants from toward the eastern edge tend to have heads loosely arrayed and radiate and stems single. The two forms have been recognized as weakly defined species (or varieties), the former as Senecio foetidus and the latter as S. hydrophiloides. They intergrade so completely that they are best treated as a single, variable taxon. The use of the epithet foetidus for the broadly conceived single species was based on a bibliographic misunderstanding; the correct epithet is hydrophiloides (T. M. Barkley 1978; A. Cronquist 1994).

In 1900, Thomas Howell gave the name Senecio oreganus to a collection from Lake Labish, near Salem, Oregon. The area has seen much disturbance and development since Howell’s time, and the plant appears to be extinct in the region. The collection is difficult to exclude from S. hydrophiloides, and the collection is here regarded as an odd outlier of S. hydrophiloides, which is known chiefly from east of the Cascade uplift. Howell’s collection and therefore the name S. oreganus also have been treated within S. sphaerocephalus (T. M. Barkley 1978; A. Cronquist 1955); that attribution appears to be in error. The “type” materials are now in the herbarium of Oregon State University in Corvallis.

Selected References

None.

Lower Taxa

None.
... more about "Senecio hydrophiloides"
not tailed +, rounded +  and obtuse +
papillate +
scarious +
usually ovate +  and lance-linear +
corymbiform +, loose +  and congested +
indeterminate +  and determinate +
Theodore M. Barkley† +
Rydberg +
tapered +
15 cm150 mm <br />0.15 m <br /> (20 cm200 mm <br />0.2 m <br />) +
5 cm50 mm <br />0.05 m <br /> (15 cm150 mm <br />0.15 m <br />) +
elliptic;broadly lanceolate +
2cm;7cm +
winged;nerved;ribbed +
barbellulate +  and smooth +
white +  and stramineous +
purplish +, reddish +, white +, ochroleucous +, yellow +  and white rarely reddish +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
angled +, 5-ribbed +, prismatic +  and cylindric +
fertile +  and bisexual +
fertile +  and bisexual +
Alta. +, B.C. +, Calif. +, Idaho +, Mont. +, Nev. +, Oreg. +, Utah +, Wash. +  and Wyo. +
1200–2200 m +
hairy +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Damp hillsides, non-alkaline meadows, seepage sites +
discoid +  and radiate +
indeterminate +
heterogamous +  and homogamous +
glabrescent +  and glabrous +
each +  and sessile +
0.5 cm5 mm <br />0.005 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
turbinate;campanulate +
cauline +  and basal +
reduced +
erect;recurved +
deltate +
dentate to pinnatifid +  and entire +
dentate +  and denticulate +
2-carpellate +
persistent +
Flowering spring–early summer. +
mostly oblong +  and lanceolate or linear +
0.4 cm4 mm <br />0.004 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
Mem. New York Bot. Gard. +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
exalbuminous +
2 +  and 4 +
appendaged +  and truncate +
papillate +
Senecio foetidus +, Senecio foetidus var. hydrophiloides +  and Senecio oreganus +
Senecio hydrophiloides +
species +
campanulate +
denticulate +  and serrate or toothed +
100 cm1,000 mm <br />1 m <br /> (140 cm1,400 mm <br />1.4 m <br />) +
30 cm300 mm <br />0.3 m <br /> (100 cm1,000 mm <br />1 m <br />) +
shrub +  and subshrub +