Sproßbildung einiger Orchidaceae der Kola-Halbinsel (Nordwest-Rußland): Shoot structure of some Orchidaceae of the Kola-PI. (N Russia)

Summary A study of the root-tuber, rhizome and root-cluster orchids demonstrated essential structural resemblance of their monocarpic shoots and particularities of their regeneration. Species studied here are of different growth forms but belong to the same “long-stalked sympodial” model (sensu T. I. S erebrjakova 1977) of shoot formation. On the basis of the bud structure and the spatial orientation of annual shoots three growth patterns of this model were described: the additive, circular and pendulum growth mechanisms. The root-cluster growth form represents the transitional form between the short-rhizome and the root-tuber growth forms. The root-tuber growth form seems to be the evolutionary youngest. The spatial structure of orchid populations of different growth forms can be explained through the specialities of their shoot development.