Submerged bryophytes and angiosperms of the River Tweed and its tributaries

Summary An attempt is made to present a picture of the distribution of all submerged bryophytes and angiosperms recorded from flowing waters of the Tweed River System between 1971 and 1974. Data were collected from 300 consecutive 0–5 km lengths in the main river and 270 selected lengths from 11 tributaries, and the distribution patterns of the 30 species are represented pictorially. The relative numbers and abundances of bryophytes and angiosperms recorded from various stretches of the main river and its tributaries are compared. Data are also included summarising results of some statistical tests which attempted to show if the distribution of certain species could be correlated with changes in physical and chemical parameters of the environment.