@article {129,
	title = {Biosystematic studies on the genus Isoetes (Isoetaceae) in Japan. II. Meiotic behavior and reproductive mode of each cytotype},
	journal = {American Journal of Botany},
	volume = {83},
	year = {1996},
	note = {Cited By (since 1996):13Export Date: 11 November 2013Source: Scopus},
	month = {1996///},
	pages = {1309 - 1322},
	abstract = {Meiotic behaviors and reproductive modes of Japanese Isoetes were studied. The hexaploid (2n = 66) and the octaploid (2n = 88) of I. japonica consistently formed 33 and 44 bivalents, respectively, at diakinesis and/or metaphase I in both micro- and megaspore mother cells. The tetraploid (2n = 44) of I. sinensis formed 22 bivalents and its hexaploid made 33 bivalents in both types of spore mother cells. At diakinesis and/or metaphase I of microspore mother cells in I. asiatica with 2n = 22, 11 bivalents were detected. Because behaviors of meiosis in all cytotypes mentioned above were quite regular and plants yielded normal-appearing spores, they should reproduce sexually. Aneuploids of I. japonica with 2n = 87 formed 43 bivalents and one univalent, and I. sinensis with 2n = 65 formed 32 bivalents and one univalent in microspore mother cells. Meiosis of both cytotypes was almost regular and yielded microspores of normal appearance. In the heptaploid (2n = 77) of I. japonica, a configuration of 22 bivalents and 33 univalents was detected in micro- and megaspore mother cells, and various irregularities were observed throughout the meiotic divisions. Therefore, the genomic formula of the heptaploid is symbolized as AABBCDE, and the heptaploid is a sterile F 1 hybrid between the hexaploid (AABBCC) and the octaploid (AABBDDEE) of I. japonica. Since diploid and even-numbered polyploids regularly formed bivalents and odd-numbered ones displayed irregularities, allopolyploidy should act as a significant speciation mechanism in this genus.},
	keywords = {Chromosome, Hybrid, Isoetes, megasporogenesis, meiosis, microsporogene sis, polyplo id, reproductive mode},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0030475989\&partnerID=40\&md5=996182a1723b75d447e3a2137006f7bd},
	author = {Takamiya, M. and Watanabe, M. and Ono, K.}
}
@article {131,
	title = {Biosystematic studies on the genus Isoetes (Isoetaceae) in Japan. III. Variability within qualitative and quantitative morphology of spores},
	journal = {Journal of Plant Research},
	volume = {109},
	year = {1996},
	note = {Cited By (since 1996):10Export Date: 11 November 2013Source: Scopus},
	month = {1996///},
	pages = {281 - 296},
	abstract = {Qualitative 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.},
	keywords = {Cytotype, Isoetes, Megaspore, Microspore, Palynology, Polyploidy},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0030495119\&partnerID=40\&md5=def6cedc48f4ad43b95e6e4eb0cbc75e},
	author = {Watanabe, M. and Takamiya, M. and Matsusaka, T. and Ono, K.}
}
@article {142,
	title = {Biosystematic studies on the genus Isoetes in Japan I. Variations of the somatic chromosome numbers},
	journal = {Journal of Plant Research},
	volume = {107},
	year = {1994},
	note = {Cited By (since 1996):17Export Date: 11 November 2013Source: Scopus},
	month = {1994///},
	pages = {289 - 297},
	abstract = {The 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. {\textcopyright} 1994 The Botanical Society of Japan.},
	keywords = {Aneuploid, Chromosome number, Cytogeography, Isoetes, Polyploid, Pteridophyta},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-21844512580\&partnerID=40\&md5=5cb0d06bc24499fb20d76da2946e91ea},
	author = {Takamiya, M. and Watanabe, M. and Ono, K.}
}
