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=def6cedc48f4ad43b95e6e4eb0cbc75e02039nas a2200241   4500008004100000245010200041210006900143260001200212300001400224490000700238520129100245653001101536653001201547653001401559653001501573653001401588653001101602653001901613100001501632700001701647700001601664856011701680       2010                        eng d00aMorphology and ultrastructure of megaspores and microspores of isoetes sehnemii fuchs (lycophyta)0 aMorphology and ultrastructure of megaspores and microspores of i  c2010///  a341 - 3520 v823 aThe morphology and wall ultrastructure of megaspores and microspores of Isoetes sehnemii that grows in Brazil were analyzed as part of the study of the Isoetaceae present in Southern South America. The observations were performed with light, scanning and transmission electron microscopes. The megaspores are trilete, 350-450μm in equatorial diameter. The surface is reticulate. In section, the sporoderm is 100μm thick including the ornamentation. The wall is composed of a siliceous perispore, which consists of short fused flatten, elements forming a three-dimensional mesh. The exospore has two zones of different structure. The endospore is fibrillar. The microspores are monolete, 21-27μm in equatorial diameter. The sporoderm is composed of a sporopollinic rugulate perispore. A space between the para-exospore and the exospore is evident. The exospore is compact. The endospore is fibrillar. The ultrastructural analysis akes hoologies evident concerning structure and organization of the layers belo the perispore in both spore types. A possible similarity and stability in the ultrustructure of the present spores and fossils could be also inferred. In addition, there would be a correlation among the plant habitat, the spore ornamentation and the geographic distribution.10aBrazil10aIsoetes10aLycophyta10aPalynology10aSculpture10aSpores10aUltrastructure1 aMacluf, C.1 aMorbelli, M.1 aGiudice, G.  uhttp://www.scopus.com/inward/record.url?eid=2-s2.0-77954194457&partnerID=40&md5=1434918a400d7fc28cb2b2ec5338958d