The development of shoots in Phragmites communis Trin.

In aerial shoots of Phragmites communis Trin., final height,and often growth-rate, depend on the width of the emergent budwhich determines the basal diameter of the mature stem. In theearly stages there is internal competition for food reservesand smaller shoots may be harmed. Growth is faster during the early phase of growth, and it isincreased in wider buds, warmer weather, and more humid habitats.Any of these factors may be of over-riding importance, e.g.a summer-emerged shoot grows faster than a spring one of equalwidth. Minor fluctuations in environment have more effect earlythan later. New nodes develop more rapidly late in the yearthan early.