Fruct. Sem. Pl. 2: 461, plate 173, fig. 7. 1791. 1791
Annuals (biennials, or perennials) [shrubs, subshrubs], (5–)20–120 cm (sometimes rhizomatous). Leaves basal and/or cauline (mostly cauline at flowering), alternate; usually sessile; blade margins entire or ± dentate to serrate. Heads radiate [disciform or discoid], in corymbiform, racemiform, or paniculiform arrays. Involucres hemispheric to campanulate, [3–]5–10[–20+] mm diam. Phyllaries persistent (reflexed in fruit), in (2–)3–4+ series, unequal to subequal. Receptacles flat, smooth or minutely alveolate, epaleate. Ray florets (10–)20–30[–60+], pistillate, fertile; corollas yellow, laminae 1.5–2+ mm. Disc florets (9–)40–100[–150+]; corollas yellow, lobes 5. Cypselae ellipsoid (abruptly constricted distally; often glandular distally); pappi persistent, outer of basally connate, ± erose scales (usually forming cups), inner of distinct (fragile), barbellate or flattened bristles. x = 7, 9, 10.
Introduced; Europe, Asia, Africa.
Species 100+ (1 in the flora).
Pulicaria arabica (Linnaeus) Cassini (Vicoa auriculata Cassini) was collected in Alabama, California, and Florida in the late 1800s. It does not appear to have become naturalized at any of those locations (A. Cronquist 1980; J. E. Arriagada 1998).
Pulicaria dysenterica (Linnaeus) Bernhardi was collected in the late 1800s as a ballast weed in New Jersey and in Pennsylvania. It was collected in the 1920s growing on the margins of a marsh in Maryland. Although it is widely cultivated for its insecticidal properties, there is no evidence that it has ever become established in the flora (J. E. Arriagada 1998).
Pulicaria vulgaris Gaertner was collected as a ballast weed in New Jersey in 1879. No other collections of the species from North America are known to me.