Plagiothecium undulatum Waved Silk-moss

A fairly large, dioicous pleurocarpous moss which grows in acidic woodlands, usually on the ground, sometimes on the bases of tree trunks and occasionally on soil covered rock. It is also found in heathland.  The pale green colour and the long mostly unbranched stem give it a very distinctive look and the leaves, which have a very short double nerve, are undulated conspicuously. It is widespread and common in much of Britain, predominantly in the west and north, and it is found throughout Wales. In West Glamogan it is most frequent in the acidic woodlands of Neath Port Talbot but much less common in Gower. While it is a characteristic species of upland oak woodlands, often in association with Dicranum majus and Rhytidiadelphus loreus, in West Glamorgan it is most abundant in humid Sitka Spruce forests where it forms large, attractive carpets. Prior to afforestation and maturation of spruce forests on the South wales Coalfield it was only found in scattered locations. The expansion of its range into conifer forests in the last 50 years has been remarkable. Sporophyte capsules are occasional.