Shrubs , fragrant. Branches spreading-ascending, terete, pubescent to glabate, glandular when young. Leaves mostly deciduous, occasionally persistent, ± deeply pinnatifid; stipules present, deciduous or ± persistent. Leaf blade linear-lanceolate, with 2-10 rounded to pointed lobes, membranous, glabrous or densely pubescent and glandular. Inflorescences cylindric; staminate eventually flexuous, pistillate globose-ovoid at maturity, appearing before leaves; bracts ovate or cordate, glabrous or variously pubescent. Flowers unisexual, staminate and pistillate usually on different plants, occasionally on same plants. Staminate flowers: stamens 3-8, shorter than subtending bract, filaments free or slightly fused. Pistillate flowers: ovary subtended by persistent bract and 2 linear-subulate bracteoles at anthesis, bracteoles accrescent and developing 4-8 tertiary bracteoles (= scales of other authors), these longer than and concealing fruit; styles 2, elongate. Fruits oblong-ovoid, smooth (without protuberances), waxless. x = 8.
Pistillate fl initially subtended by a primary bract and bracteoles, but an indefinite number (often 4) of linear-subulate secondary bracteoles arising adaxially to each of the latter, ±coalescent below, accrescent, elongating and persistent so that the pistillate infl forms a bur; ovary glabrous, without papillae; achene smooth, hard; rhizomatous, aromatic shrubs with deciduous, pinnately lobed, stipulate lvs. Monospecific.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.