Bryum barnesii

Different gemma formation in Bryum barnesii Woods



Gemma formation in the Bryum bicolor complex is strongly influenced by environmental conditions. The morphology and number of bulbiferous gemmae in leaf axils are the major characters separating Bryum dichotomum Hedw. (incl. B. bicolor Dicks.) from Bryum barnesii Woods. Some authors claim that these characters intergrade and treat B. barnesii as a synonym of B. dichotomum. To evaluate the variability in bulbils shape and number within a population, B. barnesii was studied under controlled conditions. Bulbils were germinated on sterilized soil in a greenhouse and in a climate incubator. Protonemal growth, number of shoots, number of shoots with bulbils and number of bulbils per shoot were counted and variability of bulbil shape was investigated. The number of bulbils per leaf axil was constant, but the shape of bulbils and leaves showed greater seasonal variability than mentioned in the descriptions of B. barnesii. In the climate incubator bulbils also developed directly from a dense secondary protonema. Both types of bulbils can float on the water surface for several days and are therefore suitable for long distance dispersal along streams and shorelines with varying water levels. Apart from the number of bulbils per leaf axil, morphological differences between B. barnesii and B. dichotomum are small. Molecular analyses should be used to evaluate the relationship between these taxa..





bryophytes, Bryum bicolor complex, vegetative propagules



Research Project Information

Runtime: 2004-02-15 until 2006-07-15
Project coordination: Dr. Christian Dolnik
Cooperation partner(s): BRYOPLANET



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