Scentless mayweed
Tripleurospermum perforata (Tripleurospermum inodorum, Matricaria inodora, Matri)

Height: 20–80 cm (8–32 in.). Usually 1-stemmed. Stem erect–ascending, branching, glabrous, green.
Flower: Single flower-like, usually 3–5 cm (1.2–2 in.) capitula, surrounded by involucral bracts. Capitula’s ray-florets white, tongue-like, tip shallowly 3-toothed; disc florets yellow, tubular, small. Stamens 5. Pistil of 2 fused carpels. Involucral bracts different lengths, 1–1.5 mm (0.04–0.06 in.) broad, light brown–white margins. Disc stacked, full. Capitula 1–20 borne in a corymbose cluster.
Leaves: Alternate, short-stalked–stalkless. Blade 2–3 times pinnately lobed (–with leaflets), glabrous, lobes (or leaflets) long, thread-like narrow, sharp-pointed.
Fruit: Flattish, ridged achene, with 2 round–angular oil spots, tip sometimes with small, membranous ring.
Habitat: Fields, fallow land, lawns, wasteland, roadsides, yards, gardens.