Shrubs or small trees , evergreen, glabrous or obscurely pubescent. Leaves alternate, simple, without stipules, petiolate. Leaf blade fragrant (especially when bruised or crushed), translucent-dotted, ovate to lanceolate, pinnately veined, thin to leathery, margins entire. Flowers bisexual, axillary or from main stem or older branches, solitary, pedunculate; peduncle bracteolate; perianth hypogynous; tepals 7-33, imbricate, distinct, in 2-3 series, outer tepals small, sometimes bractlike, innermost more petaloid; stamens 4-50, hypogynous, distinct, in 1-several series; filaments ligulate to terete; anthers basifixed, 4-locular, dehiscence longitudinal; pollen 3-aperturate; pistils simple, 5-21, distinct, closely laterally appressed in 1 series on convex axis, attached obliquely by broad base; placentation nearly basal; ovule 1 per locule; stigmatic surface adaxial. Fruits aggregates of radially arranged follicles; dehiscence adaxial. Seed 1 per follicle, ellipsoid to obovoid, somewhat flattened laterally; endosperm copious, oily; embryo minute.

Aromatic oils obtained from some members of this genus are used for flavorings and as carminatives; oil derived from Illicium anisatum Linnaeus is poisonous. Chinese star-anise, used widely for flavoring wine and cooking, is obtained from I . verum Hooker f. (J. Hutchinson 1973; C. E. Wood Jr. 1958). The Chinese drug pa-chio-hui-hsiang, used to treat vomiting, epigastric pain, and abdominal colic, is derived from ripe fruits of I . verum (Xiao P. G. 1989).

Illiciaceae are considered closely allied to Schisandraceae. Anatomic details of wood of Illiciaceae and Schisandraceae are nearly indistinguishable, differing only in details linked to the climbing habit of members of the latter (I. W. Bailey and C. G. Nast 1948; S. Carlquist 1982; A. C. Smith 1947). Studies of fossil pollen led J. W. Walker and A. G. Walker (1984) to conclude that Illiciaceae and Schisandraceae are allies of Winteraceae. Based on analysis of nucleotide sequences from the plastid gene rbc L, however, M. W. Chase et al. (1993) and Qiu Y. L. et al. (1993) concluded that Illiciaceae and Schisandraceae are closely allied and closely related to Austrobaileyaceae but distant from Winteraceae.