Further revision is needed. C. giganteum and C. centrorubrum (Makino) Nakai are closely related Asian taxa that are provionally mapped here together. Compared to typical album (FNA 4), these taxa are relatively robust, with stems up to 2-3 m, and more densely farinose; leaves are up to 15 cm long, often distinctly 3-lobed (versus weakly lobed), and dentate to entire (versus densely dentate); seeds are reportedly smaller, on average. C. centrorubrum (or album var. centrorubrum Makino) is a densely reddish-farinose plant (Ohwi 1975) that has been rarely reported in North America, but it is represented by colls. (MM for WKY) from HARL (around Pine Mt. Settlement School) and JEFF (widely escaped from cultivation of R. Cassell). This taxon may be much more widespread, but it is frequently difficult to distinguish from giganteum (FNA 4).