Erigeron engelmannii

A. Nelson

Bull. Torrey Bot. Club 26: 247. 1899.

Common names: Engelmann’s fleabane
Endemic
Treatment appears in FNA Volume 20. Treatment on page 290. Mentioned on page 259, 270.

Perennials, 3–20 (–30) cm; taprooted, caudex branches relatively short and thick. Stems erect, loosely to closely, sparsely to moderately strigose (hairs 0.1–0.9 mm), usually minutely glandular (glands barely evident), sometimes eglandular. Leaves basal (usually persistent) and cauline (petioles prominently ciliate at least on proximal portions, hairs spreading, thick-based); basal blades linear-oblanceolate, 20–100 × 1–4 mm, margins entire, faces strigose, eglandular; cauline usually restricted to proximal 1/2 of stems, slightly reduced distally. Heads 1 (–3). Involucres 3.5–5 (–6) × 7–12 mm. Phyllaries in 2–3 (–4) series, coarsely hirsuto-villous, sparsely to moderately minutely glandular. Ray-florets (35–) 45–100; corollas white, sometimes pink or bluish, 5–10 mm, laminae (0.8–1.1 mm wide) primarily reflexing, sometimes also weakly coiling at the tips. Disc corollas (2.5–) 2.7–4.2 mm (throats indurate and inflated, densely puberulent). Cypselae 1.4–1.8 mm (oblong), 2-nerved, faces sparsely strigose; pappi: outer usually of narrow scales, sometimes 0 or of setae, inner of 12–20 bristles.


Phenology: Flowering (Apr–)May–Jul.
Habitat: Dry, sandy or rocky sites, prairies, often with sagebrush, rabbitbrush, juniper, pinyon-juniper, salt desert shrub
Elevation: 1300–2500 m

Discussion

Plants from Chaffee and Fremont counties, Colorado, have strigose leaves and the compact habit of Erigeron engelmannii but sparsely spreading-hirsute stems; they may be intermediate between E. engelmannii and E. concinnus. Unusual variation in the pappi of E. engelmannii also suggests that the species needs study and better definition.

A. Cronquist observed that “Erigeron engelmannii intergrades completely with E. pumilus, yet has two geographic subspecies of its own, and shows no distributional similarity to the [taxa] of E. pumilus,” and that E. engelmannii is “smaller and more delicate, with shorter finer hairs, and [has] smaller heads with usually fewer ligules.”

Selected References

None.

Lower Taxa

None.
... more about "Erigeron engelmannii"
not tailed +, rounded +  and obtuse +
distinct +
subequal +
scarious +
usually triangular +  and linear +
usually deltate +  and lanceolate +
paniculiform +, corymbiform +  and loose +
indeterminate +  and determinate +
Guy L. Nesom +
A. Nelson +
2 cm20 mm <br />0.02 m <br /> (10 cm100 mm <br />0.1 m <br />) +
linear-oblanceolate +
0.1 cm1 mm <br />0.001 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
decurrent +
linear;lanceolate oblanceolate or spatulate +
rugulose +  and muricate +
Engelmann’s fleabane +
not 2-lipped +  and actinomorphic +
bluish +, pink +  and white +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
beaked +, 2-ribbed +  and 5-ribbed +
subterete +, oblong +  and oblong-obovoid compressed +
fertile +  and bisexual +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.27 cm2.7 mm <br />0.0027 m <br />) +
0.27 cm2.7 mm <br />0.0027 m <br /> (0.42 cm4.2 mm <br />0.0042 m <br />) +
fertile +  and bisexual +
Colo. +, Idaho +, Utah +  and Wyo. +
1300–2500 m +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Dry, sandy or rocky sites, prairies, often with sagebrush, rabbitbrush, juniper, pinyon-juniper, salt desert shrub +
disciform +  and discoid +
in loose , corymbiform or paniculiform arrays +  and singly +
indeterminate +
heterogamous +  and homogamous +
each +  and sessile +
0.5 cm5 mm <br />0.005 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
turbinate;hemispheric +
0.7 cm7 mm <br />0.007 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
petiolate +  and sessile +
cauline +  and basal +
erect;spreading +
deltate +
Not (?) +  and Scarious (?) +
2-carpellate +
Flowering (Apr–)May–Jul. +
3-nerved +  and 1-nerved +
hirsuto-villous +
narrowly elliptic +  and linear-lanceolate +
Bull. Torrey Bot. Club +
bearing subulate enations +, hairy +  and bristly +
exalbuminous +
prostrate +  and decumbent +
appendaged +  and truncate +
papillate +  and smooth +
Achaetogeron +  and Trimorpha +
Erigeron engelmannii +
Erigeron +
species +
inflated +  and tubular +
20 cm200 mm <br />0.2 m <br /> (30 cm300 mm <br />0.3 m <br />) +
3 cm30 mm <br />0.03 m <br /> (20 cm200 mm <br />0.2 m <br />) +
tree +, shrub +  and subshrub +