Possibility of natural hybridization between Cyperus iria L. and Cyperus microiria Steud.
Examination of the progeny of 8 and 12 strains of C. iria and C. microiria, resp., collected as seed in the Okayama and Tottori Prefectures of Honshu and grown in pots in a field on the Okayama University campus in June-Aug. 1986, revealed the development of hybrid plants. These plants exhibited an intermediate form between the 2 species as regards the shape of floral scales and floret density. They also had longer spikelets and a greater number of florets, although seed fertilities were evidently lower than those of the parent species. The seeds of new plants were dormant in each of the reciprocal crossings between C. iria and C. microiria, and the dormancy could be broken by stratification at 15°C for 1 month (a character that was probably inherited from the dormant parent, C. microiria). Progeny of the new-type plants also showed clear segregation in spikelet characteristics and floret morphology.