The differentiation of subspecies in Bolboschoenus maritimus based on the inflorescence structure

The importance of inflorescence structure as a diagnostic feature was studied to distinguish Bolboschoenus maritimus (L.) Palla subsp. maritimus and B. maritimus subsp. compactus (Hoffm.) Hejný in Dostál. The subspecies were determined using characters in the fruits and the level of agreement with inflorescence characters was compared. The following characters were recorded: the length of spikelets and of peduncles of the inflorescence, the number of peduncles of the inflorescence, the number of sessile and peduncled spikelets. From these primary characters, relative characters were derived. Plants from field populations and cultivated plants collected from localities throughout the Czech and Slovak Republics were studied, as well as changes in inflorescence morphology after transplanting. Significant differences were found between both subspecies in most of the characters measured in the field populations as well as in the cultivated plants. The number of peduncles of the inflorescence, the ratio between the number of sessile and peduncled spikelets and the length ratio of sessile spikelets and peduncles of the inflorescence were found to be most suitable to use for the determination of both subspecies. Plants of subsp. compactus were found to be more variable in most characters compared with subsp. maritimus. The field populations of subsp. maritimus were homogeneous in most characters (negligible intrapopulation variation), and the influence of habitat was found to be significant only in some characters. The populations of subsp. compactus showed greater variation in most characters within populations and were not significantly influenced by habitat.