Abstract: The nocturnal-flowering group of Hemerocallis was treated as including three separate species， H．lilioasphodelus，H.citrina and H．minor in the Florae Reipublicae Popularis Sinicae Vol．14(1980)．However it is difficult to distinguish them from one another by a single feature，such as the flower number，length of perianth tube，diameter of tuberous roots，for they are strongly overlapping．In the present paper，numerical analysis was made of nine morphological characters and karyotype divergences which are of taxonomic significance as shown in the study of H． fulva and its two varieties (Xiong and Chen，1992)，based on dry and living materials from China．In addition，geographical distribution pattern of the three taxa studied shows that they seem to be different geographical races or allopatric ecotypes in a topocline，since they inhabit a climate gradient from warm and moist to cold and drought condition．As a result，the present authors tend to consider it more reasonable to treat them as a single species，H．lilioasphodelus，with three subspecies，that is， H．lilioasphodelus ssp．lilioasphodelus,H．lilioasphodelus ssp． citrina (stat．nov) and H．lilioasphodelus ssp．minor(stat．nov．)

Key words: Hemerocallis, H. lilioasphodelus, Morphology, Karyotype, Geographic distribution