Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Genus Description - Fls mostly perfect, 4-merous; sep usually minute; pet small, valvate; style well developed; stigma capitate; fr a drupe, the stone bilocular (except in C. canadensis) but often only 1-seeded; fls in cymose or cymose-paniculate infls or, by reduction of the branches, in umbelliform or head-like clusters. (Chamaepericlymenum, Svida, Cynoxylon) 50+, widespread but mainly N. Temp.
Named hybrids include C. ×acadiensis Fernald (C. alternifolia × sericea), C. ×arnoldiana Rehder (C. amomum var. schuetzeana × racemosa), and C. ×slavinii Rehder (C. rugosa × sericea). Others include C. amomum × stricta, C. drummondii × stricta, C. amomum var. schuetzeana × drummondii, C. drummondii × racemosa, and C. racemosa × stricta.