Arcyria denudata
This bright, red-brown slime mould is one of the most common species in Eastern Canada and the adjacent United States. It fades to dull brown in age and is similar in size and shape to the Grey Arcyria and fruits in similar habitats. You can sometimes find both species fruiting on the same log. In Arcyria species, the sporangial heads are a mixture of spores and capillitium. The capillitium is a thread-like material that supports the spore mass and aids in the dispersal of spores. In Arcyria the capillitial threads are ornamented with rings and spines (click here). These take up and lose moisture with changes in relative humidity and this causes differences in tensions along the length of the threads. To satisfy these tensions, the threads readjust and the wriggling action propels the spores away from the sporangium. The spores are then carried by air currents to new sites for growth.