02130nas a2200241   4500008004100000245014400041210006900185260001200254300001400266490000800280520133600288653001301624653001201637653001401649653001501663653001501678653001501693100001701708700001701725700001801742700001201760856011601772       1996                        eng d00aBiosystematic studies on the genus Isoetes (Isoetaceae) in Japan. III. Variability within qualitative and quantitative morphology of spores0 aBiosystematic studies on the genus Isoetes Isoetaceae in Japan I  c1996///  a281 - 2960 v1093 aQualitative and quantitative characteristics of mega- and microspores from all the cytotypes of Japanese Isoetes are described based on the voucher specimens whose chromosome numbers were known. In I. japonica, the hexaploid possessed reticulate megaspores and levigate microspores, while the octaploid and the heptaploid had echinate microspores. Mega- and microspores of the hexaploid and the octaploid were of normal appearance, while those of the heptaploid displayed polymorphism. The tetraploid and the hexaploid of I. sinensis resembled each other, since they both possessed cristate megaspores and echinate microspores. Echinate megaspores and levigate microspores characterized the diploid I. asiatica. The spore size was largely variable within each cytotype, while the size of the megaspores varied more than that of the microspores. The microspore length was closely correlated with polyploid level. In I. sinensis, the mean microspore length of the tetraploid was 27.6 μm while that of the hexaploid was 31.9 μm, hence these two cytotypes were easily distinguishable. In the hexaploid I. japonica, variations in mega- and microspore size displayed geoclinal variation showing a positive correlation (r=0.43-0.55) with the longitude and the latitude of the populations. A palynotogical key for cytotypes is presented.10aCytotype10aIsoetes10aMegaspore10aMicrospore10aPalynology10aPolyploidy1 aWatanabe, M.1 aTakamiya, M.1 aMatsusaka, T.1 aOno, K.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-0030495119&partnerID=40&md5=def6cedc48f4ad43b95e6e4eb0cbc75e01798nas a2200229   4500008004100000245010400041210006900145260001200214300001400226490000800240520106000248653001401308653002201322653001801344653001201362653001401374653001701388100001701405700001701422700001201439856011701451       1994                        eng d00aBiosystematic studies on the genus Isoetes in Japan I. Variations of the somatic chromosome numbers0 aBiosystematic studies on the genus Isoetes in Japan I Variations  c1994///  a289 - 2970 v1073 aThe somatic chromosome number of three Japanese species of Isoetes, I. asiatica, I. japonica and I. sinensis, was determined in 199 individuals from 49 populations. The chromosome number of I. asiatica was 2 n=22, confirming previous reports. However, I. japonica and I. sinensis displayed a diversity in chromosome number. Six cytotypes, 2 n=66, 67, 77, 87, 88 and 89, were found in I. japonica; 2 n=67, 87, 88 and 89 are new counts in the genus Isoetes. The plants with 2 n=66 were the most frequent (72% of total individuals examined) and were distributed throughout Honshu and Shikoku. The plants with 2 n=88 occurred in western Honshu and a limited region in northeastern Honshu where the plants with 2 n=77 were also found. In contrast, four cytotypes, 2 n=44, 65, 66 and 68, were found in I. sinensis. The chromosome numbers of I. sinensis were reported here for the first time. The plants with 2 n=44 occurred only in Kyushu, while the plants with 2 n=66 were found throughout a large area of western Japan. © 1994 The Botanical Society of Japan.10aAneuploid10aChromosome number10aCytogeography10aIsoetes10aPolyploid10aPteridophyta1 aTakamiya, M.1 aWatanabe, M.1 aOno, K.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-21844512580&partnerID=40&md5=5cb0d06bc24499fb20d76da2946e91ea