A contribution to the taxonomy of the Agrostis mertensii-flaccida complex (Poaceae) in Japan

ArticleinJournal of Plant Research 88(2):65-87 · June 1975with5 Reads
DOI: 10.1007/BF02491243
Abstract
Morphological, cytological and field observations on 20 populations of theAgrostis mertensii-flaccida complex were reported. The plants were found to be diploid, tetraploid, hexaploid, septaploid or octoploid with a basic chromosome number of x=7. The diploids were most wide-spread and diverse in habitat and morphology. The tetraploids were discovered in 3 sites in Hokkaido. The hexaploids and octoploids occurred on various mountains in central and northern Honshu as well as in some of Hokkaido. A septaploid plant was found on Mts. Daisetsu. Pollen studies showed that diploid and tetraploid plants had smaller grains when compared with those of the hexaploids and the octoploids. The diploids, though variable in morphology and ecology, seemed to belong to a taxon which was more or less deviated morphologically from the diploid or tetraploid taxa growing outside Japan. The tetraploids were indistinguishable morphologically from the diploids. The hexaploids in Honshu, which were clearly different from the hexaploids in Hokkaido in morphology, possessed unique spikelet features. The majority of the octoploids were found to be distinct from the diploids and the tetraploids in the length ratio of anther/lemma. Some morphological “marker” features which distinguished between the diploids and the octoploids were observed for all of their sympatric populations, though such “marker” traits varied according to the localities. The taxonomic and evolutionary relationships between these Japanese entities and the taxa growing outside Japan were discussed. In conclusion, setting aside some plants which require further investigations, the Japanese plants concerned were arranged into 3 species:Agrostis flaccida Hack., including 2X and 4X together with 3X previously reported;A. tateyamensis Tateoka, sp. nov., implying 6X in Honshu;A. mertensii Trin. including 8X. A description ofA. tateyamensis was given.
  • [Show abstract] [Hide abstract] ABSTRACT: Populations of theAgrostis flaccida-mertensii complex in Hokkaido were examined as part of the taxonomic study of this complex, which has a wide range and comprises a polyploid series of 2x–8x (x=7). The principal aim was to clarify the taxonomic status of hexaploids growing in Hokkaido. Field explorations were made in the mountains and on the coasts in Hokkaido, and the materials were gathered from 19 localities. The occurrence of four cytotypes (2x, 4x, 6x, 8x), as well as some triploids and septaploids, of this complex in Hokkaido was confirmed, and the ranges of respective cytotypes were delineated. Morphological examinations showed that diploids, triploids and tetraploids are referable toAgrostis flaccida and octoploids toA. mertensii. The hexaploids of Hokkaido were morphologically different fromA. flaccida and also from the related hexaploid species,A. tateyamensis, distributed in Honshu. The hexaploids were quite similar to octoploidA. mertensii in all the morphological features examined and also in habitat preference. Septaploids were sterile hybrids between hexaploids and octoploids. A conclusion was drawn that the hexaploid plant of Hokkaido should be grouped with the octoploid in one and the same species,Agrostis mertensii Trin.Agrostis mertensii in this amended sense is discussed from a cytogeographical viewpoint.
    Article · Sep 1987
  • [Show abstract] [Hide abstract] ABSTRACT: Variation in chromosome number and morphological characters ofSedum aizoon L. var.floribundum Nakai were investigated to analyze, correlations between them. Geographical variation in chromosome number was also examined. Chromosome numbers of 189 individuals from 55 localities were counted as 2n=32, 33, 34, 48, 61, 64, 78, 80, 84, 85, 88, 93, 94, 95, 96, 97 and 102. InSedum subgenusAizoon, which has the basic number of X=8, var.floribundum of the speciesaizoon showed a polyploid series from tetraploid to dodecaploid. Tetraploids were found most frequently in this variety. More than two chromosome numbers were found in all the populations with 2n=61 or more. Tetraploids were mainly distributed in the eastern part of Japan, and higher polyploids (higher than hexaploid level except octaploids) were distributed in the western part of Japan. Thirteen morphological characters were examined in 119 individuals belonging to 30 populations. The principal component analysis and the cluster analysis of these characters indicated that populations with similar chromosome numbers were not always morphologically similar. Ten morphotypes can be recognized based on the combination of chromosome number and morphological characters. ThusS. aizoon var.floribundum can be regarded as a polyploid-aneuploid complex.
    Article · Mar 1990
  • [Show abstract] [Hide abstract] ABSTRACT: The present paper summarizes the chromosome numbers found in 110 species of the genus Agrostis L. This register aims to extract and index the karyological data published throughout the world. The information is drawn from ca 190 papers known to the author in 1997. Short notes on the taxonomy and karyology of selected species and tables with some general statistical data concerning the occurrence of defined ploidy level, B-chromosomes and aneuploidy are given.
    Article · Jan 1997 · The Botanical Magazine Tokyo