Inter-population variation in morphology and physiology in the cosmopolitan mossBryum argenteumHedw.

Aspects of the morphology and temperature relations of clones isolated from temperate, tropical and polar populations of Bryum argenteum are compared. The clones were similar in their responses to frost and to high temperature stress, and a day/night temperature regime of 22/15°C in each case proved the most favourable of those tested for protonema growth and shoot production. Antarctic and tropical provenances both showed slow protonema growth and shoot production at 5/–5°C. Antarctic clones were in general the most vigorous of those tested in a range of environments.The clones proved morphologically distinct from each other in collateral cultivation, differing in protonema morphology, shoot arrangement and leaf morphology. There was correlation between variation in the cultures and in the original field populations in some characters such as length of the leaf apiculus but other differences between the field populations, notably in stem length, leaf length and nerve excurrence, were not maintained in cultivation.