Senecio flaccidus Less.
By Frankie Coburn, Native Plants of Arizona 2007
Common names:
Threadleaf groundsel,
felty groundsel, sand wash
groundsel, comb butterweed, threadleaf butterweed, old man, yerba cana,
squawweed, creek senecio, cenicillo
threadleaf ragwort(1), Douglas ragwort, mono ragwort (2).
Family:
Asteraceae(2).
Synonymy:
Senecio
flaccidus
var. douglasii (DC.) B.L. Turner & T.M. Barkl., S. flaccidus
var. flaccidus, S. flaccidus var. monoensis (Greene) B.L.
Turner & T.M. Barkl..Each of these varieties having multiple synonyms (1,2).
Etymology:
Senecio is from the Latin “senes” meaning “old man” in reference to the white tiny hair-like growth at
the apex of the ovary (3). Flaccidus in Latin means “flabby” or “lacking
firmness” likely referring to the flexibility and flaccid nature of the
branches of this species(4).
Identification
Growth form:
Short lived, fast-growing perrenial subshrub to shrub (1).
Roots: Woody, perennial tap roots with broad crowns(5).
Stem:
Woody usually
branched, often straggly becoming decumbant to 1m but dying back to less
than 50cm from ground. Stems can be photosynthetic(2,5).
Leaves:
Alternate, narrow and thread-like often deeply lobed reaching 12cm with
small, white hairs, giving the leaves a grey color. (2,6).
Inflorescence/flowers:
Produces numerous radiate
heads, 3–10 per cluster; main phyllaries ± 13mm, sometimes 21, 5–10+ mm;
outer phyllaries ± prominent; 817 yellow ray flowers with rays 10 to 15mm
long and up to 40 yellow disc flowers (2,6).
Fruit:
Cylindric; ribs shallow, wind-borne with white, fluffy
pappus(2,6).
Similar
species:
Senecio flaccidus
has three varieties defined by both morphology and geographic distribution
that were once recognized as separate species (5).
Ecology
Life history:
Woody, short lived, fast-growing perennial subshrub to shrub, known to be
evergreen in the southern part of it’s range (2,5).
Native/introduced:
Native
Photosynthetic
pathway:
Phenology:
Flowering summer-fall.
Distribution:
Found in dry, sandy
or rocky plains, open basins, washes and canyons, colonizing disturbed areas
from 800 to 2400m. Found throughout Arizona; also in CO., KA, NM, OK, TX,
UT, CA, and NV; Mexico(2,5).
Uses
Toxic to livestock and humans due to
pyrrolizidine alkaloids,
although with the right preparation it has been found to be beneficial
medicinally. Hopi used to pound the leaves with a hot rock and smear the
paste on sore muscles. Ground leaves were also used by the Hopi to treat
pimples. Navajo have the same uses and also use it to treat arthritis,
rhuemetism and boils. Internally it has been used by the Rio Grande
Puebloans as a tea to treat severe stomach ache and by Navajo singers in
ceremony. Navajo also used the fuzzy stems and flowers to knock spines from
cacti fruits. Considered a climax species for desert grasslands (2,3,7).
References
1. USDA, NRCS. 2007. The PLANTS Database (http://plants.usda.gov, 24, November 2007). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
2.. Epple, A. O. 1995. A Field Guide to the Plants of Arizona. Falcon Publishing. Helena, Montana. (<http://www.fs.fed.us/global/iitf/pdf/shrubs /Senecio%20flaccidus.pdf4> Nov 28, 2007)
3. Kearney, T. H., R. H. Peebles, and collaborators. 1960. Arizona Flora 2nd Edition. University of California Press, Berkeley and Los Angeles, California.
4. American Heritage Dictionary of the English Language: Fourth Edition. 2000 Houghton Mifflin Company.(http://www.bartleby.com/61/77/F0157700.html Nov 28, 2007).
5. Flora of North America (http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250067486, Nov 28, 2007).
6.
The
Jepson Manual
Higher Plants of California
http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?609,1784,1801> (Nov
28, 2007)
7. Elmore, F. H. 1976. Shrubs and Trees of the Southwest Uplands. Southwest Parks and Monuments Association, Globe, Arizona.
