Morphological variations of the dimorphic fern Matteuccia struthiopteris in Norway [Dimorfinio Matteuccia struthiopteris morfologinis įvairavimas Norvegijoje]. – Botanica Lithuanica, 10(2): 107–119

The main aim of this study was to quantify morphological variations of M. struthiopteris and to investigate how different plant organs were correlated. More than 9000 plants (rootstocks) from different parts of Norway were studied. Fertile fronds (sporophylls) had developed in 14.6 % of the investigated rootstocks. A maximum of 9 sporophylls and 20 sterile fronds (trophophylls) were found on one rootstock. Intermediate fronds (partly fertile and sterile) were found on 13.6 % of the fertile plants. The plants had to reach a certain size (age) before they started to produce sporophyll, and this threshold was generally associated with more than 6 trophophylls, a trophophyll taller than 120 cm, and a rhizome thickness exceeding 6 cm. A major part of the plant‘s biomass was constituted by remaining leaf scars (trophopods) and based on their numbers; the biggest rootstock investigated was estimated to be at least 70 years.

Keywords: sporophyll, trophophyll, trophopod, rootstock, biomass.