[taxon report][distribution map][all photos][line drawing]
Scientific Name: Erigeron acomanus Spellenberg and Knight
Vernacular Name: Acoma fleabane
R-E-D Code: 3-1-3
Description: Taprooted perennial, mat-forming, 10-70 cm in diameter; leaves mostly basal, spreading or ascending, 8-30 in rosettes at ends of caudex branches, oblanceolate to narrowly obovate or spatulate, 8-23 mm long, 2-7 mm wide, round or obtuse at the tip, moderately puberulent on both surfaces; flowering stems erect, 4.5-15 cm tall, bearing 4-10 reduced leaves; heads solitary, pendulous in bud, erect in flower and fruit; involucre 5 mm high; phyllaries 25-38, lanceolatate, 2.5-4 mm long, purplish on the margins; ray flowers 16-30, white, 4.5-9 mm long; disk corollas 2.5-3 mm long, yellowish; achenes somewhat flattened, lightly hirsute; pappus of fine barbellate bristles. Flowers in July.
Similar Species: The allopatric Erigeron tener has bluish or pinkish rays and a compact, caespitose habit. Erigeron vetensis has a greater number of white, pink, or blue ray flowers and densely glandular herbage.
Distribution: New Mexico, McKinley and Cibola counties.
Habitat: Sandy slopes and benches beneath sandstone cliffs of the Entrada Sandstone Formation in piņon-juniper woodland; 2,100-2,170 m (6,900-7,100 ft).
Remarks: A Cibola County population at Bluewater Canyon is taller, less mat-forming, not consistantly monocephalic, and has an isozyme profile distinctive from that of the McKinley County populations. It may be an undescribed variant of either Erigeron acomanus or E. tener.
Conservation Considerations: A very narrow endemic, but current land uses do not significantly threaten its habitats. May occasionally be impacted by mining operations.
Important Literature (*Illustration):
*Ecosphere Environmental Services, Inc. 1995. The Farmington District endangered, threatened and sensitive plant field guide. USDI-Bureau of Land Management, Farmington, New Mexico.
Reed, S. 1996. Genetic variation and population structure in four rare species of Erigeron from the American southwest. Unpublished MS Thesis, University of New Mexico, Albuquerque.
*Spellenberg, R. and P.J. Knight. 1989. A new species of Erigeron (Asteraceae: Astereae) from central New Mexico. Madroño 36(2):115-121.
Information Compiled By:
Daniela Roth, 1999