I'm grateful to the following people whom supported me in executing this researchproject.

Albert Delfos for his stimulating ideas, his help with the preparations and his large contribution to the field work. I'm also grateful to him for making most of the inkdrawings of the originals I drew in pencil.

Ed Buys whose contribution to this research is of great importance. It was a pleasure to work with him.

Peter Coesel for his supervision, his patience and for his useful comments on this report.

The University of Tromsø  and especially Karl‑Dag Vorren for introducing us to Andøya and  helping  us  to  organize  this  investigation  and  supplying  us  with  field  workequipment.

My  wife  Marianne   for  her  field  work  assistance  and  especially  for  her encouragement and support during the ups and downs in the research progress and in my physical constitution.

My parents for lending their car (with the handy luggage carrier my father made) and for their moral support. Unfortunately, their car hardly survived the trip.

Kjell‑Einar and Alfhield Vangen for being so kind to provide us with accommodation in the school at Saura and in their caravan and also I want to thank them for their hospitality and interest

Hanny Kooijman‑van Blokland for her practical help with preparing the field work and with the microscope work. Hanny died in 1994, far too young.

Frans Kouwets for his help with difficult determinations.

Klaasjan Wardenaar and Linda Frinking for their stimulating and agreeable company during the microscope work in the former Hugo de Vries laboratory buildings at the Hortus Botanicus in Amsterdam.

Diny Winthagen and Marga Coesel for their library assistance.

Mark van Veen for his statistical advices.

Hendrine van Walbeek for multiplying this report.

Michael Nijdam for lending his notebook computer.

>> Introduction