1. Tribe Anthemideae Cass.

(Bremer and Humphries, 1993)

Plants annual, biennial, or perennial herbs, sometimes from a woody rootstock, often aromatic, the sap not milky. Stems not spiny or prickly. Leaves alternate (rarely opposite elsewhere), sometimes also in a basal rosette, sometimes appearing fasciculate, sessile or short-petiolate, not spiny or prickly. Leaf blades often lobed, the venation pinnate or palmate, with 1 or few main veins. Inflorescences terminal panicles, clusters of heads, or the heads solitary at the branch tips. Heads discoid or radiate. Involucre of 2 to several series of bracts, not spiny or tuberculate. Receptacle flat to hemispherical or conical, naked or at least some of the florets subtended by chaffy bracts, receptacle rarely long-hairy. Ray florets (when present) pistillate or less commonly sterile, sometimes inconspicuous, the corollas sometimes very short, white, cream-colored, or yellow, rarely pink. Disc florets all perfect or the innermost sometimes staminate or the outermost sometimes pistillate, the corolla yellow to greenish yellow, less commonly white or pink, the 4 or more commonly 5 short lobes spreading to ascending. Pappus of few scales or reduced to a low collar or crown, sometimes absent, when present persistent at fruiting. Stamens with the filaments not fused together, the anthers fused into a tube, each tip without a distinct appendage, each base truncate or with a pair of short lobes. Style branches usually somewhat flattened, each with a stigmatic line along each inner margin, the sterile tip short and usually truncate, often with dense, minute hairs. Fruits sometimes dimorphic (the outer series then thicker-walled and with different surface ornamentation), circular or more commonly angled in cross-section, oblong to slightly wedge-shaped in profile, sometimes ribbed, rarely appearing nearly winged, not beaked. About 110 genera, about 1,750 species, worldwide.

The tribe Anthemidae contains a number of garden ornamentals, including the numerous cultivated members of the Chrysanthemum alliance (Soreng and Cope, 1991). Some members of the tribe are pharmacologically or biochemically important and have been used as medicinal herbs, in cosmetics and shampoos, and as a source of insecticides. Similarly, because of their aromatic compounds, some species have been eaten as potherbs and garnishings or used in herbal teas and liquors. However, some members of the tribe are noxious weeds of croplands and pastures.

The taxonomy of the tribe is still not fully understood, and several of the generic complexes require further systematic and phylogenetic study. Although the breakup of the formerly large genus Chrysanthemum L. is now widely accepted (for discussion, see the treatment of Leucanthemum), the transfer of some of the species groups into Tanacetum remains controversial. Similarly, many botanists have not accepted the segregation of Seriphidium (Besser ex Less.) Fourr. from Artemisia. The generic taxonomy of the chamomiles and their relatives remains especially confusing. The present treatment of the tribe may not be entirely satisfying to readers (for it is less than satisfying to the author), and it should be regarded as an interim classification at best.

Note that the genus Hymenopappus, which was included in the Anthemidae in some of the older botanical literature, is here treated in the helenioid group of Heliantheae, following Bremer and Humphries (1993).