Hemerocallis dumortierii, H. esculenta and H. middendorfii were considered
to belong to a biological complex, and were treated as different varieties of the same species,
H. dumortierii. The present authors observed and compared the karyotypes of H. esculen-
ta and H. middendorfii. Two plant samples for each of the species were studied. One sam-
ple of H. esculenta was from Wuán County, Hebei Province, at an altitute of 1000 m, the
other from Shennongjia, Hubei Province, altitute 2100 m. The two samples of H. middendorfii were respectively from Antu County, at an altitute of 700 m, and Tonghua, altitute
500 m, in Jilin Province. The karyotypes are 2n＝2x=22=12m+8sm+2T for H. escu-
lenta, while 2n＝2x＝22=10m+6sm+4st+2T for H. middendorfii. The karyotypical
difference between the two taxa was obviously not intraspecific but interspecific. Based on
the karyotype data as well as the morphological and phytogeographical data available, it is
considered that H. esculenta and H. middendorfii should be recognized as different
species, instead of different varieties of the same species as in literature, and that H. mid-