Journal of Plant Research

, Volume 107, Issue 3, pp 269–274 | Cite as

Hybrid sterility between two isozymic types of the fernCeratopteris thalictroides in Japan

  • Shigeo Masuyama
  • Yasuyuki Watano
Original Articles


JapaneseCeratopteris thalictroides are composed of two allopatric entities called the south type and the north type which are isozymically distinct. Both types are tetraploid at 2n=156. To examine the crossability of these isozymic types, artificial hybridization was conducted among ten representative populations. Allozymes of PGI were used as markers to identify the hybrids among populations. Hybrids within the north type produced normal-shaped spores whose germination rate reached 60.7 to 96.0%. In contrast, hybrids between the north type and the south type formed irregular-shaped spores which were aborted with a low germination rate of 0.0 to 7.0%. It is thus evident that hybrid sterility is present between these types. Morphological analyses revealed that the two types were part of a continuous cline of variability and hence morphologically inseparable. The two types can thus be regarded so far as cryptic species that are morphologically indistinguishable but reproductively isolated.

Key words

Allozyme Ceratopteris thalictroides Cryptic species Fern Hybrid sterility Reproductive isolation 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Grant, V. 1981. Plant Speciation, 2nd ed. Columbia Univ. Press, New York.Google Scholar
  2. Haufler, C.H. 1989. Species concepts in pteridophytes: summary and synthesis. Amer. Fern J.79: 90–93.Google Scholar
  3. Haufler, C.H. andWang, Z. 1991. Chromosomal analysis and the origin of allopolyploidPolypodium virginianum (Polypodiaceae). Amer. J. Bot.78: 624–629.Google Scholar
  4. Haufler, C.H. andWindham, M.D. 1991. New species of North AmericanCystopteris andPolypodium, with comments on their reticulate relationships. Amer. Fern J.81: 7–23.Google Scholar
  5. Lloyd, R.M. 1974. Systematics of the genusCeratopteris Brongn. (Parkeriaceae). II. Taxonomy. Brittonia26: 139–160.Google Scholar
  6. Lovis, J.D. 1968. Fern hybridists and fern hybridising II. Fern hybridising at The University of Leeds. Brit. Fern Gaz.10: 13–20.Google Scholar
  7. Masuyama, S. 1992. Clinal variation of frond morphology and its adaptive implication in the fernCeratopteris thalictroides in Japan. PI. Species Biol.7: 87–96.Google Scholar
  8. Paris, C.A., Wagner, F.S. andWagner, W.H. Jr. 1989. Cryptic species, species delimitation, and taxonomic practice in the homosporous ferns. Amer. Fern J.79: 46–54.Google Scholar
  9. Paris, C.A. andWindham, M.D. 1988. A biosystematic investigation of theAdiantum pedatum complex in eastern North America. Syst. Bot.13: 240–255.Google Scholar
  10. Soltis, D.E. andSoltis, P.S. 1989. Polyploidy, breeding systems, and genetic differentiation in homosporous pteridophytes.In D.E. Soltis and P.S. Soltis, eds., Isozymes in Plant Biology. Discorides, Portland, pp. 241–258.Google Scholar
  11. Wagner, W.H. Jr. andWagner, F.S. 1983a. Genus communities as a systematic tool in the study of new worldBotrychium (Ophio glossaceae). Taxon32: 51–63.Google Scholar
  12. Wagner, W.H. Jr. andWagner, F.S. 1983b. Two moonworts of the Rocky Mountains:Botrychium hesperium and a new species formerly confused with it. Amer. Fern J.73: 53–62.Google Scholar
  13. Watano, Y. andMasuyama, S. 1991. Inbreeding in natural populations of the annual polyploid fernCeratopteris thalictroides (Parkeriaceae). Syst. Bot.16: 705–714.Google Scholar
  14. Watano, Y. andMasuyama, S. 1994. Genetic differentiation in populations of the polymorphic fernCeratopteris thalictroides in Japan. J. Plant Res.107: 139–146.Google Scholar
  15. Werth, C.R. 1989. The use of isozyme data for inferring the ancestry of polyploid pteridophytes. Biochem. Syst. Ecol.17: 117–130.Google Scholar
  16. Wiley, E.O. 1981. Phylogenetics: The Theory and Practice of Phylogenetic Systematics. John Wiley & Sons, New York.Google Scholar
  17. Yatskievych, G. andMoran, R.C. 1989. Primary divergence and species concepts in ferns. Amer. Fern J.79: 36–45.Google Scholar

Copyright information

© The Botanical Society of Japan 1994

Authors and Affiliations

  • Shigeo Masuyama
    • 1
  • Yasuyuki Watano
    • 2
  1. 1.Department of General EducationTokyo Woman's Christian UniversityMitaka, TokyoJapan
  2. 2.Department of Biology, Faculty of ScienceKanazawa UniversityKanazawaJapan

Personalised recommendations