Trailing Fleabane

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.

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. 2n = 18, 27, 36, 45, 54.

Erigeron nudiflorus Buckley

Erigeron flagellaris is a North American species of flowering plants in the family Asteraceae known by the common names trailing fleabane.

Erigeron flagellaris is widespread across much of western North America. It has been found in western Canada (Alberta + British Columbia), the western United States (primarily the Rocky Mountains and Intermountain regions) and northern Mexico (from Chihuahua east to Tamaulipas and south to Durango).

Erigeron flagellaris is a small perennial herb rarely more than 15 centimeters (8 inches) in height. Most of the leaves are clustered around the base of the stems. The plant reproduces by means of stolons, which are horizontal stems running along the surface of the ground, forming new roots and shoots at frequent intervals. Thus the plant can form extensive mats of clones. Each stem usually produces only 1 flower head per stem, though occasionally 2 or 3. Each head contains as many as 125 white ray florets surrounding numerous yellow disc florets.