MORPHOLOGY OF FRUITLETS OF FAR EASTERN SPECIES OF THE GENUS <i>POTENTILLA</i> (ROSACEAE)

Abstract

The study of fruitlet morphology is carried out in 16 species of the genus Potentilla occurring in the Amur Region (Priamurye) and Primorye Territory. The sculpture of the fruitlet surface is shown to have diagnostic significance. The position, shape of the stylodium and the ratio of its length to the length of the fruitlet can be successfully used as diagnostic characters to distinguish the subgenera of the genus Potentilla. The inaccuracy of S.V. Yuzepchuk (1941) concerning the stylodia in the diagnoses of sections Niveae and Argenteae in the “Flora of the USSR” is corrected. The results of the research have shown that the stylodia in the species of these sections are short, rather thick, no longer than a mature fruitlet, instead of thin and long, as it was specified by S.V. Yuzepchuk. The presence of glands on the fruitlets of the members of section Pensylvanicae (P. approximata, P. conferta) can serve as a reason for the distinguishing this section within the subgenus Potentilla. The degree of expression of papillary outgrowths (short and long) in the lower part of the stylodium is a diagnostic trait of section Potentilla. The presence of covering hairs on the dorsal and ventral sides of the fruitlets in P. semiglabra, as well as a wide wing-like outgrowth on the dorsal side of the fruitlets in P. asperrima can be used in the taxonomy of the genus Potentilla as specific diagnostic traits. The species of Potentilla (P. amurensis, P. asperrima, P. centigrana) with a diploid set of chromosomes (2n = 14) are characterized by scarious and wing-like outgrowths on the fruitlets.