Arcyria denudata, commonly known as carnival candy slime mold, is a species of myxomycete slime mold in the family Arcyriaceae. It is one of the most common species of slime molds, and can be found in temperate environments worldwide.
Description
Sporangium with the lower half of the peridium intact and the capitillium bursting from the apex
The plasmodium of A. denudata is white. The sporophores are upright, stalked sporangia that may be gregarious or crowded in large colonies. Each sporangium is ovate to cylindrical, 2-6 mm tall by 0.4-1.2 mm wide, and pinkish-red to brick-red in color, but fading to brown as it matures. The slender stalks are striate, 0.5-1.5 mm long, and may be the same color as the sporangium or darker.
Sporangia with exposed capillitia after the peridia have dehisced
The peridium is membranous, with an inner surface that may be smooth or covered with warts or spines. As the fruiting body matures, the peridium breaks apart along the circumference, sometimes leaving behind a persistent cap at the apex. As the peridium dehisces, the pinkish-red capillitium underneath expands. Without their peridia, the fruiting bodies often resemble cotton candy, leading to the species' common name 'carnival candy slime mold.' The hypothallus is thin and reddish brown with a silvery sheen. The capillitium consists of a network of threads, 3-4 μm thick and marked with cogs, spikes, or half-rings. It is firmly attached to the whole inner surface of the calyculus. The spores are red to reddish brown in mass and pale yellow to colorless individually. Each spore is 6-8 μm in diameter, with a few faint scattered warts.
Spores and capillitia
Life cycle
As the outer wall of the sporangium disintegrates, the spores are exposed and dispersed by wind. Insects may also play a role in dispersal. Beetles of the genus Baeocera have been observed on the sporocarps of A. denudata.
When a spore lands on plant material, it may germinate to produce a single-celled zoospore with one...
