Capillitium and Spores of Metatrichia
In Trichia and Metatrichia the capillitium is made of elator-like segments so there are many 'free' ends to be found. In Hemitrichia the capillitium forms a network so free ends are not present. In both genera there are spiral ornamentations on the capillitial threads. The threads can take up or lose moisture (water vapour). This changes tensions in the threads causing a wriggling motion that dislodges the spores and flicks them away from the sporangium to be dispersed by wind. You can see this happening if you put a fresh sporangium under the dissecting microscope and the heat of the lamp causes a violent (comparatively) wriggling action of the threads. The spores in this species are more or less spherical and minutely spiny (echinulate).