东北三肋果 dong bei san lei guo

Chamaemelum tetragonospermum F. Schmidt, Reis. Amur-Land., Bot. 148. 1868; Matricaria tetragonosperma (F. Schmidt) H. Hara & Kitamura.

Herbs, annual, 40-50 cm tall; stems usually branched from base, striate, upper parts sparsely pubescent, lower part glabrous. Lower and middle stem leaves sessile; leaf blade oblanceolate-oblong or oblong, 5-15 × 2-5 cm, 2- or 3-pinnatisect, both surfaces glabrous; ultimate segments linear-filiform. Distal stem leaves similar, smaller. Capitula solitary, terminal, several per plant, 2-2.5 cm in diam. Involucres hemispheric, 1.2-1.5 cm in diam.; phyllaries in 4 rows, abaxially glabrous, scarious margin narrow, brown, outer ones ovate-oblong, apex obtuse, middle ones narrowly oblong, apex rounded, inner ones lanceolate-oblong, apex obtuse. Ray florets white; lamina ca. 6.5 mm. Disk florets yellow, 5-lobed. Achenes brownish, triquetrous, ca. 1.5 mm, tuberculate, with 1 adaxial and 2 lateral thick ribs, abaxially and apically with 2 distinct resin sacs. Corona ca. 0.2 mm, entire. Fl. and fr. Jun-Aug.

Roadsides, sandy places by rivers; ca. 300 m. Heilongjiang, Liaoning [Japan, Russia].