161.
Erigeron flagellaris
A. Gray, Mem. Amer. Acad. Arts, n. s. 4: 68. 1849.
Trailing fleabane
Erigeron nudiflorus Buckley
Biennuals or short-lived perennials,
3—15 cm; usually fibrous-rooted, sometimes taprooted, caudices lignescent, rarely branched.
Stems
first erect (greenish proximally; usually single, simple), then producing herbaceous, leafy, prostrate runners (usually with rooting plantlets at tips, populations often becoming clonal mats), strigose (often sparsely; hairs antrorsely appressed, consistent in orientation), sometimes slightly glandular distally.
Leaves
basal (often persistent) and cauline; basal blades broadly oblanceolate to elliptic, 20—55 × 3—9 mm, cauline abruptly reduced distally, margins entire or dentate, faces strigose, eglandular.
Heads
1(—3, on proximal branches).
Involucres
3—5 × 6—13 mm.
Phyllaries
in 2—3 series, strigose to loosely hirsute, minutely glandular.
Ray florets
40—125; corollas white, often with an abaxial midstripe, often drying lilac, 4—10 mm, laminae not coiling or reflexing.
Disc corollas
2—3.5 mm.
Cypselae
0.8—1.3 mm, 2-nerved, faces sparsely strigose;
pappi:
outer of setae, inner of 10—17 bristles.
2
n
= 18, 27, 36, 45, 54.
Flowering May—Aug(—Sep). Meadows and grassy slopes, often moist, open areas in grasslands, pinyon pine, oak-pine, pine, aspen, and spruce-fir; (1700—)2100—3600 m; Alta., B.C.; Ariz., Calif., Colo., Idaho, Kans., Mont., Nebr., Nev., N.Mex., N.Dak., Okla., Oreg., S.Dak., Tex., Utah, Wash., Wyo.; Mexico.
Early season forms of
Erigeron flagellaris
may consist of a basal rosette and a single, erect, scapiform, monocephalous stem; leafy runners usually develop quickly. Many polyploids of this species are indistinguishable from diploids; some polyploids have features suggestive of genetic influence of
E. tracyi
.
