Differentiatie van Scirpus maritimus L. in Nederland

Scirpus maritimus from inland localities can be characterized by having 4—6 peduncles and very characteristic fruits: narrow, dark brown to almost black, in cross-section sharply triangular. The variability of the fruits within a sample and between samples of different places is small. These plants should be considered the paramorph (HUXLEY, 1940) ‘maritimus’. Scirpus maritimus from the Frisian island of Schiermonnikoog is characterized by a smaller number of peduncles (0—2) and fruits which are small, broad, brown, semi-spherical to slightly triangular, with a great variability within and between the samples. We can consider them as ‘compactus’, but have to bear in mind that the differences between these plants and plants from the really saltish areas of the S. W. coast of Holland with 2 to 3(—4) peduncles are not very striking. Especially in the freshwater tidal area of the Biesbosch only intermediate types occur. In conclusion there seems to be a continuous intergradation between the paramorphs maritimus and compactus, at least in the morphological characteristics, which means that in the Netherlands S. maritimus shows a clinal variation, probably in correlation with the habitat.