Abstract: Armeniaca hongpingensis IS A CRITICALLY ENDANGERED SPECIES DISTRIBUTED ONLY IN HONGPING TOWN, SHENNONGJIA, HUBEI PROVINCE. ACCORDING TO FLORA OF CHINA, A. hongpingensis MAY BE A NATURAL HYBRID OF A. mume AND A. vulgaris, AND A. mume var. bungo MAY ALSO BE A HYBRID OF THEM. HOWEVER, THERE IS NO MORPHOLOGICAL STUDY ON THE RELATIONSHIP BETWEEN A. hongpingensis, A. vulgaris, A. mume and A. mume var. Bungo. THROUGH FIELD INVESTIGATIONS, 21 QUANTITATIVE CHARACTERS AND 15 QUALITATIVE CHARACTERS OF LEAF, FLOWER, FRUIT, KERNEL AND BRANCH WERE OBTAINED AND CLUSTER ANALYSIS WAS CARRIED OUT. THE RESULTS SHOWED THAT EITHER PAM CLUSTER OR UPGMA CLUSTER ANALYSIS COULD CLEARLY DIVIDE THEM INTO FOUR SPECIES, INDICATING THAT THERE WERE OBVIOUS DISTINGUISHING CHARACTERS AMONG THEM. IN THE PRINCIPAL COMPONENT ANALYSIS, THE ABSOLUTE WEIGHT VALUES OF ANNUAL BRANCH COLOR AND HAIR-COVERING STATUS, HAIR-COVERING STATUS OF LEAF AND FRUIT, LEAF SHAPE INDEX (LEAF SHAPE, LEAF TIP, LEAF BASE) AND SURFACE CHARACTERS OF KERNEL IN THE FIRST THREE PRINCIPAL COMPONENTS WERE ALL ABOVE 0.9, INDICATING THAT THESE TRAITS PLAYED IMPORTANT ROLES IN THE CLASSIFICATION OF FOUR Armeniaca SPECIES. VIA ELECTRON MICROSCOPE, THE POLLENS WERE monads, isopolar, radially symmetrical, tri-colporate. POLLEN SURFACE OF A. vulgaris, A. mum and A. mume var. bungo is striate-ornamented, while POLLEN OF A. hongpingensis IS DISCONTINUOUS STRIPED AND HAS unconspicuous PERFORATION. THE EPIDERMAL CELLS OF THE LEAVES OF THE FOUR PLANTS ALL SHOWED STRIATE KERATINIZATION. COMPARED WITH OTHER SPECIES, THE STRIPES ON THE CELL SURFACE OF A. hongpingensis WERE OFTEN CURVED, OVERLAPPED AND WITHOUT FIXED DIRECTION. ACCORDING TO THE RESULTS OF CLUSTER ANALYSIS AND MICROMORPHOLOGY CHARACTERS, A. hongpingensis SHOULD BE TREATED AS AN INDEPENDENT SPECIES FROM A. vulgaris and A. mume.