Trans. Amer. Philos. Soc., n. s. 7: 309. 1840.
Perennials, 20–100 cm; taprooted, woody, with caudexlike branches 2–15 cm, or leafy stems arising directly from roots; single plants usually bowl-shaped, with up to a 65 cm lateral spread. Stems erect or ascending (often purple, distal branches stiff, spreading-ascending, without axillary leaf tufts), glabrous or sparsely strigose (hairs straight, ascending-appressed), sometimes minutely glandular distally. Leaves cauline; blades 1-nerved (often sharply folding in narrower forms), filiform or linear to oblanceolate, 10–65 × 1–5 (–10) mm, relatively even-sized (mid and distal longer than internodes), margins entire, ciliate (cilia ascending-appressed, thick-based), faces glabrous or sparsely strigose, eglandular. Heads 1 or 2–5 in loosely corymbiform arrays. Involucres 3.2–6.5 × 7–12 (–14) mm. Phyllaries in 3–5 series (outer: margins stramineous, with distal, greenish, rhomboid patches; inner: margins narrow, scarious), glabrous or moderately to densely strigoso-hirsute, sparsely and obscurely to densely and prominently minutely glandular. Ray-florets 15–60; corollas white to blue, 5–15 mm, laminae not coiling or reflexing. Disc corollas 3.5–5.5 mm (throats slightly indurate, not inflated). Cypselae (1.8–) 2.2–3 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 19–34 bristles.
Calif., nw Mexico
Varieties 5 (5 in the flora).
Erigeron foliosus and its close relatives, including varieties, were mapped in detail by G. L. Nesom (1992b).
|1||Phyllaries 0.5–0.8 mm wide, margins usually thick or only narrowly scarious, abaxial faces sometimes sparsely and obscurely glandular||> 2|
|1||Phyllaries 0.8–1 mm wide, margins usually broadly scarious, abaxial faces densely and prominently glandular||> 3|
|2||Leaves (30–)40–60 mm, apices usually acute, often mostly with 1-directional orientation to one side of stems; inner phyllaries (4–)5–6 mm; ray corollas 8–13 mm||Erigeron foliosus var. hartwegii|
|2||Leaves 20–40(–50) mm, apices usually rounded, without a prominent 1-directional orientation; inner phyllaries 3.2–4.5 mm; ray corollas 6–10 mm||Erigeron foliosus var. foliosus|
|3||Phyllaries glabrous; leaves mostly 1–2 mm wide||Erigeron foliosus var. confinis|
|3||Phyllaries moderately to densely strigoso-hirsute; leaves mostly 2–4 mm wide||> 4|
|4||Leaf faces sparsely to moderately strigose; phyllaries with prominent, raised, orange-resinous midnerves; ray corollas 7–10 mm||Erigeron foliosus var. franciscensis|
|4||Leaf faces glabrous or glabrate except for ascending-ciliate margins and midveins; phyllaries usually without distinct, orange-resinous midnerves; ray corollas 10–15 mm||Erigeron foliosus var. mendocinus|