2. Matricaria discoidea de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 6: 50. 1838.
同花母菊 tong hua mu ju
Chamomilla suaveolens (Pursh) Rydberg; C. discoidea (de Candolle) J. Gay ex A. Braun; Santolina suaveolens Pursh 1813, not Matricaria suaveolens Linnaeus 1755.
Herbs, annual. Stems 5-30 cm tall, erect or ascending, branched in upper part or from base, glabrous or sparsely pubescent below capitula. Stem leaves sessile; leaf blade oblong or oblanceolate, 2-3 × 0.8-1 cm, 2-pinnatisect; ultimate segments shortly linear, both surfaces glabrous. Capitula homogamous, irregularly corymbose or solitary at apex of branches, pedunculate; peduncle 0.5-1 cm. Involucres cup-shaped; phyllaries in 3 rows, equal, oblong, abaxially glabrous, scarious margin hyaline, apex obtuse. All florets bisexual, pale yellow-green, tubular, 5-lobed. Achenes oblong, somewhat curved, ca. 1.5 mm, apex obliquely truncate, with 2 or 3 adaxial thin white ribs and 1 red thin stripe on each side. Pappus represented by a white corona. Fl. and fr. Jul. 2n = 18.
Forests, roadsides, near houses. Jilin (Baicheng, Hunchun), Liaoning, Nei Mongol [Bhutan, Japan, Kazakhstan, Korea, Russia; N Asia, Europe, North America].
Matricaria matricarioides (Lessing) Porter cannot be applied to the American taxon; M. matricarioides was originally published as Artemisia matricarioides Lessing, a new name for Tanacetum pauciflorum Richardson (see S. Rauschert 1974), itself a synonym of T. huronense Nuttall. W. Greuter (pers. comm.), who accepts M. discodea, considers Rauschert’s treating Artemisia matricarioides as homotypic with T. pauciflorum as equivalent to a lectotype designation.