UV-B absorbing pigments in spores: biochemical responses to shade in a high-latitude birch forest and implications for sporopollenin-based proxies of past environmental change - Fraser, WT; Sephton, MA; Watson, JS; Self, S; Lomax, BH; James, DI; Wellman, CH; Callaghan, TV; Beerling, DJ (Polar Research, 2011)