LIFE-HISTORY AND VEGETATIVE REPRODUCTION IN CAREX

The genus Carex is made up of c2000 species of herbaceous perennials occurring in a wide range of habitats throughout the world but especially in north temperate and arctic regions. They are modular organisms that reproduce vegetatively by rhizomes or other means, some species forming extensive and long-lived clones, others tufts, clumps, or tussocks of various sizes. Most temperate and arctic species have shoots formed during the previous year, some emerging in autumn, others remaining below ground until spring. The maximum shoot life span for temperate species c24 months but mortality is very high; sometimes 90% of shoots do not live for the whole 2-yr life span. Shoots in arctic-alpine regions live longer, perhaps as long as 5-7 yr, with lower mortality. Mortality is caused by differences in time of emergence flowering, animal grazing, the age of the genet, and internal competition through the rhizome system. -from Author