This winter- or spring-annual is relatively new to North America, and now placed in a genus with only two species, from southern Europe and east Africa (W and citations). The species appears to have spread into the Ohio Valley from the east during the 1980s (Thieret & Baird 1985), including the Scioto Valley at first in Ohio (A. Cusick, pers. comm.). Increase occurred rapidly in the Bluegrass region of Ky. during 1990s, especially along mowed roadsides and in adjacent fallow fields. It now occurs in virtually all counties of Ky. and in adjacent states, though it remains infrequent or rare in more hilly regions (Thompson et al. 2013, pers. comm.). In the herbarium, diagnostic characters for M. alliacea versus T. arvense (FNA 7, W) are its hairy stems, at least basally (versus glabrous), fruits smaller (mostly 5-8 x 3-5 mm versus 9-20 x 7-16 mm), less broadly winged (ca. 0.5-1.5 versus 3.5-5 mm at apex), and seeds alveolate (versus striate). On the road, it is easy to identify since plants become distinctly yellowish when mature (versus glaucous), and usually occur in dense masses on exposed soil, mostly during April (earlier than arvense, mostly in May)..