This is widely distributed as a native plant on lowlands of southeastern states, and it has also been planted further north. It is a sexual diploid (2n = 34) or apomictic triploid; possible varieties and hybrids deserve further study (Sargent 1905, 1922; Britton & Brown 1913; F, St, FNA 9 ). C. viridis is about the only species in series Virides, but it is highly variable, with unresolved intraspecific taxonomy, and there appear to be occasional hybrids with species in other series. Typical viridis has oblong-ovate leaves with moderate lobing, and bright red fruit. The more southwestern var. ovata (Sarg.) Palmer (with unlobed or shallow-lobed ovate leaves and yellow-red fruit) was reported from w. Ky. in Britton & Brown (1913); it has sometimes been treated as a species by USDA (PL). A coll. from BALL (KY) with more deeply serrated or lobed leaves may be referable to var. lutescens Palmer ex Gleason; but see also var. interior (Beadle) Palmer. A coll. from MCRA (check MO) with bright yellow fruits was named forma padukensis Palmer & Pickens. Var. lanceolata (Sarg.) E.J. Palmer (with lanceolate to oblong leaves) is centered in the lower Mississippi Valley and reported from w. Tenn. Some plants have been referred to the closely related (and dubious) species, C. nitida (Engelm.) Sarg. That taxon may be distinguishd by its thorns few or lacking; relatively large thick glossy leaves (perhaps sometimes glaucous below); larger flowers and larger more pruinose fruit (F, St, FNA 9), suggesting hybridization with Crus-gallii or Punctatae. C. nitida is reportedly a triploid that originates from Ill., Mo. and Ark., but it appears to have become widely cultivated and confused with more typical viridis (especially the cultivar "Winter King"), or with hybrids of viridis and crus-galli (PL; Dirr 1997, FNA 9; see also images at mobot.org/ gardeninghelp/). Such trees have often been planted in urban landscapes of c. Ky and may be occasionally escaped.