Variation of population type in Phragmites communis Trin. Phragmites communis. 1970. Annals of Botany. 34, 14758.
The four main categories of mature populations of Phragmites communis Trin. are the dense tall stand, the sub-optimal one, the depauperate sparse stand and the restricted sparse stand. The depauperate represents the first and the sub-optimal the second stage in the development of a dense stand. Sub-optimal stands occur where one or more habitat factors are unfavourable; restricted ones where competition or shortage of nutrients, water, and so on, severely restrict the formation of lateral shoots; and depauperate ones are typical of grazed areas.
An advancing margin in an unsatisfactory habitat is indistinguishable from a restricted stand, except for the orientation of proximal growth. At the other extreme, in an open, optimum habitat, the annual advance, commonly of 1-2 m, is of very dense shoots, showing various characters rare in established populations. There is no set 'advancing behaviour', merely the response of rhizomes to the conditions for bud stimulation in each place, which may be less or more favourable than in the hinterland, depending on the habitat.