抄録
Samples of the aquatic floating fern Azolla japonica and its relatives (sect. Azolla) growing in 73 localities of Japan were analyzed by allozyme electrophoresis. Six allozyme types were recognized: AW, BW, BZ, TA, TO and YA types. Compared to the International Rice Research Institute (IRRI) accessions of Azolla by allozymes, the BZ and BW types had the same allozyme patterns as those of A. caroliniana and an artificial hybrid Azolla, respectively; It was supposed that both types had escaped from Azolla introduced to Japan for agricultural use on rice fields. The YA and AW types had very similar allozyme patterns to those of A. filiculoides and A. microphylla, respectively. The TA and TO types shared all allozyme bands except one. The TA and TO types were suggested to be closely related to A. rubra by allozyme comparison. Morphologically, it was suggested that numbers of septa in glochidia (spikelets on male massulae) differentiates the TA type from A. rubra, although only one sample of the TA type was observed. The TA (and possibly TO) type might be an independent species of genus Azolla, or true A. japonica.
