Stalked puffball-in-aspic

Appearance

The appearance of the fruit bodies has been compared to amphibian eggs or "small red tomato[es] surrounded by jelly". They consist of a bright red, globose head atop a net-like stipe, covered in a thick gelatinous layer. These fruit bodies are initially hypogeous, but emerge from the ground as the stipe continues to expand.

The head is up to 2 cm in diameter and typically nearly round, although in some populations, it is visibly oval and may be slightly smaller or larger. The internal structure of the head is complex, sometimes described as an exoperidium and endoperidium that each possess sublayers, and sometimes as distinct layers.

The outermost is a yellowish, translucent coating of jelly-like material 4 to 9 millimetres thick, somewhat similar to a gelatinous universal veil. Below this coating is a thin, cinnabar-red membrane.

As the mushroom ages, these outer layers break down and fall away from the head. Pieces of the red membrane become embedded in the remaining gelatinous material, giving them the appearance of small red seeds. This process reveals the endoperidium, a tough, non-gelatinous layer that does not break apart. When first revealed, it has a powdery, bright red surface that weathers to orange or pale yellow as the powder wears away. Bright red apical ridges or rays form a peristome.

Like the head, the stipe is covered in a gelatinous outer layer. The stipe itself consists of a number of anastomosing gelatinous strands, giving the structure a reticulate or spongy appearance. These strands vary in color from red to yellow-brown, and fade with age.

The stipe is 1 to 2 cm thick and 1.5 to 4 cm long, although some or all of this length may remain buried.

Naming

At least in North America, "Calostoma cinnabarinum" is distinctive and easily recognizable. Two other species of "Calostoma" also occur in the eastern United States. "C. lutescens" has a thinner gelatinous layer and a predominately yellow middle layer, or mesoperidium, with the red color confined to the peristome.

It also possesses a well-defined collar at the base of the spore case, a longer stipe, and globose, pitted spores. "C. ravenelii" is not gelatinous, but instead has warts adorning the spore case, and is smaller than "C. cinnabarinum". It also has a reddish peristome but is otherwise clay-colored. Unlike "C. lutescens", the spores of "C. ravenelii" cannot be distinguished from those of "C. cinnabarinum" except through the use of atomic force microscopy.

More representatives of the genus are present in Asia. At least nine species have been recorded from mainland India, some of which also overlap "C. cinnabarinum"'s range in Indonesia, Taiwan, or Japan. Many of these species can be readily distinguished by macroscopic features.

"C. japonicum" is pinkish orange and lacks a gelatinous outer layer, while both "C. jiangii" and "C. junghuhnii" are brown. However, others require microscopic features of spore shape and ornamentation for identification. Unlike the uniformly elongated spores of "C. cinnabarinum", "C. guizhouense" possesses both elliptical and globose spores. "C. pengii" differs primarily in the pattern of ornamentation on its spore surface.

Distribution

Widely distributed, "Calostoma cinnabarinum" can be found from Massachusetts south to Florida in the United States. Its range extends at least as far west as Texas, with possible populations in the Southwest, but is most common in the Appalachian Mountains where it becomes more frequent with increasing elevation.

It is also present in Eastern Mexico, where it grows in the subtropical cloud forests of Veracruz and Hidalgo. In Central America, it is known from Belize's Chiquibul National Park, the cloud forests of Baja Verapaz and El Quiché in Guatemala, and Panama.

The species is also recorded in South America, from Colombia as far southeast as Brazil, where it is described as rare. It has also been collected from a disjunct population in Asia, where it has been recorded from seven provinces in mainland China, mostly in the southeast, as well as from Indonesia, Taiwan, Japan, and Jirisan in South Korea.

Uses

As with all members of its genus, "C. cinnabarinum" is generally considered inedible by field guides. Because the fruit bodies begin development underground, they are too tough for consumption by the time they are visible, and their appearance may be considered unappetizing.