98. Filago Linnaeus, Sp. Pl. 2: 927, 1199. 1753; Gen. Pl. ed. 5, 397. 1754.
Herba impia, cotonnière, cottonrose [Latin filum, thread, and -ago, possessing or resembling, alluding to abundant cottony indument]
James D. Morefield
Annuals, (1–)5–40 cm. Stems  1, ± erect, or 2–7[–10+], ± ascending [prostrate]. Leaves cauline [basal]; alternate; blades lanceolate to oblanceolate [spatulate or ± round]. Heads in (dense, spheric [hemispheric]) glomerules of [2–]8–35+ in ± dichasiiform arrays [borne singly]. Involucres 0 or inconspicuous. Phyllaries usually 0, rarely 1–4, unequal (similar to paleae). Receptacles cylindric to clavate (heights [2–]5–15 times diams.), glabrous. Pistillate paleae (except usually innermost) ± persistent [falling], ± erect to ascending; bodies with 5+ nerves (nerves ± parallel, obscure), lanceolate to ovate, open to ± folded (each at most enfolding, not enclosing a floret); wings erect to recurved (apices acuminate to aristate). Innermost paleae usually all pistillate, in some species bisexual and pistillate, persistent or tardily falling, usually 5, erect to ascending [spreading] (scarcely enlarged) in fruit, shorter than other pistillate paleae; bodies lanceolate to ovate. Pistillate florets [12–]27–40+. Functionally staminate florets 0. Bisexual florets (1–)2–9(–11); corolla lobes 4, ± equal. Cypselae brown, ± monomorphic: terete to ± compressed, cylindric to ± obovoid, usually straight, not gibbous, faces papillate to muricate [glabrous, smooth], dull; corolla scars apical [subapical]; pappi: outer pistillate 0, inner pistillate and bisexual of [3–]13–21 bristles (visible in heads). x = 14.
Species 12(–23) (2 in the flora): introduced; Europe, w Asia, n Africa, Atlantic Islands, introduced in North America, Australia.
See discussion of Filagininae following the tribal description (p. 385).
The name Filago has been used also for the genus now usually recognized as Evax Gaertner. Here Filago, in the narrow sense, contains twelve Old World species. Six species long included in Filago in North America are here separated as Logfia.
Filago species grow in open, dry or somewhat moist habitats of arid, semiarid, Mediterranean, and humid-temperate to subtropical climates. The species in the flora grow in disturbed habitats; neither appears to be aggressively weedy.
Wagenitz, G. 1969. Abgrenzung und Gliederung der Gattung Filago L. s.l. (Compositae–Inuleae). Willdenowia 5: 395–444. Wagenitz, G. 1976. Two species of the "Filago germanica" group (Compositae–Inuleae) in the United States. Sida 6: 221–223.