Abstract:
The Poaceae contains an ecologically and taxonomically diverse array of species (s10 000 species and 655 genera) whose distributions range from the warm tropics to within the Arctic circle. Grass-dominated biomes support a rich biological community of grasses in association with seasonal herbaceous £owering plants and limited drought and ¢re-resistant arboreal components. Grasses and their associated species within grassland ecosystems possess a broad array of physiologies and ecologies including variable quantum yield e¤-ciencies and adaptations to frequent disturbance (herbivory and ¢re). These ecosystems currently cover a substantial part of the Earth's surfaceand, because they are highly productive, play a vital role in modern biogeochemical cycles.