The genus Isoëtes L. (Lycophyta, Isoëtaceae): Synthesis of karyological data

Angelo Troia, Angelo Troía

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


A synthesis of relevant karyological data regarding the genus Isoëtes is given, with an up-to-date check list of chromosome numbers including 152 records referring to 67 taxa (62 species and 5 infraspecific taxa) and 16 hybrids. Total of different chromosome counts (considering two or more cytotypes for certain taxa, excluding hybrids) is 80. Probable base number is x = 11, even though x = 10 and x = 12 have been proposed for certain species. On the basis of data here summarized, the mean percentage of polyploidy is 61.2%; 31 taxa are diploids (38.8%), 28 are tetra-1ploids (35.0%), 8 are hexaploids (10.0%), with a few species each which are tri-, penta-, octo-, deca- and dodeca-ploids. These data are briefly discussed in the frame of the evolution of the genus: palaeopolyploidy did not play a primary role, autopolyploidy seems rare, allopolyploidy is an active mechanism of speciation especially in aquatic species. Correlation between size of cells (spores and stomata) and ploidy level is also discussed.
Original languageEnglish
Pages (from-to)201-218
Number of pages18
Publication statusPublished - 2001

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Ecology
  • Plant Science


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