De eendagsexcursie naar Saasveld-Gammelke op 5 november 2016

On November 5th 2016 the society visited an area west of the city of Oldenzaal, famous for its famous vascular flora in the middle of the 20th century. Since that time agriculture has intensified, and particularly wet nature suffered from this, as brooks became ditches etc. To improve water retention conditions in a changing climate, in 2012 - 2015 water courses have been deregulated. The first locality we visited (Gammelkerbroek, N52 18.9 E6 49.7), consists of an old brook forest. Less epiphytes than expected were recorded, perhaps due to bad light conditions caused by rainy and very cloudy weather. However, also due to the moist conditions, one of the more remarkable findings was a fine patch of Cryphaea heteromalla, all the leaves spreading (Fig. 1). The same twig also hosted a stand of Platygyrium repens, not very common in this region. In the afternoon, a second locality was visited, Handijksmeden (N52 19.4 E6 50.1). Here we spent a couple of hours on a stretch not larger than ca. 70 × 35 m. The topsoil had been removed about one year earlier. Apart from some sparse vascular plant vegetation with typical plants like Gnaphalium luteo-album, the vegetation was made up mainly by a large number of pioneer bryophyte species, colonizing a slightly undulating soil made up of rusty sand and loam. The first bryophyte that struck our eyes was Phaeoceros carolineanus with numerous thalli and the typical capsules. Thallose hepactics included Fossombronia wondraczekii and F. incurva, Pellia endiviifolia and Riccardia incurvata. In the meantime, such acrocarpous species as Atrichum tenellum, Pohlia annotina and Pleuridium subulatum were found. The bottom of a dried pool revealed Riccia sorocarpa, R. glauca and R. canaliculata. Some ten meters further and somewhat higher, large stretches of Pogonatum aloides with capsules (Fig. 2) were found. Altogether the species list for this grid cell (5×5 km) raised from 119 to 144 bryophyte species, which makes this a memorable excursion.