Series: Belgian bryophyta

Tortula muralis (NL: Gewoon muursterretje / EN: Wall Screw-moss) is one of the first (and commonest) mosses that beginners will find. It grows in patches, tufts and neat cushions less than 1 cm tall. A long, smooth, silvery, excurrent nerve projects from the rounded leaf tip, making the moss look hoary grey when dry. The tongue-shaped leaf blade is 2–3.5 mm long, and twists and curls when dry, but the leaves spread away from each other when moist. The margins are recurved almost to the tip. Narrowly cylindrical capsules develop from spring to autumn. They are held erect on a 1–2 cm long, purple seta (yellowish when young like in the image), with a long peristome twisted into a spiral. It is the commonest moss on many mortared or base-rich walls – both of brick and stone – and can tolerate some shade. It also grows on concrete, roof tiles and other man-made structures, as well as outcrops of natural, base-rich rock, and much less commonly on trees and wood.

Image: Schilde (BE) - 01/03/2011