ARACHNIACEAE 



Fruit bodies exposed; peridium single, very thin, crumbling at maturity. Gleba 

 with distinct chambers lined by the hymenium, these chambers forming at maturity a 

 mass of minute, separate, hollow peridioles which crumble and escape like grains of 

 sand. Capillitium and sterile base none. 



This family is most nearly related to the Lycoperdaceae, from which it differs in 

 the simple peridium, absence of capillitium, and presence of peridioles. The peridioles 

 in Pisolithus are of a very different nature, being solid masses at all stages and without a 

 hymenium. We are including in the family only the genus Arachnion, as Arachniopsis 

 and Eolocotylon are not yet well enough known to be placed. If the former genus is 

 good and Long's description is accurate, it is very different from Arachnion, and if 

 Lloyd is right in thinking it the same as Arachnion (Myc. Notes, p. 1134) it need not be 

 considered. Eolocotylon may be related to Arachnion, and if so the family description 

 will have to be modified by the omission of peridioles. 



ARACHNION Schw. 



This genus is characterized by the peculiar nature of the contents of the peridium 

 at maturity. It is filled not with the typical gleba consisting of capillitium and spores 

 that are found in the Lycoperdons, but with a mass of granular particles like grains of 

 sand. They are grayish or ash-colored, and look like a mass of sandy earth. These 

 granules are peridioles or little sacks containing the spores. Each particle consists of a 

 woven web of hyphae enclosing a minute chamber around the walls of which are borne 

 the basidia pointing inwards, thus showing a close relationship to Lycoperdon. In 

 youth the structure is like that of Lycoperdon, the empty chambers being separated by 

 tramal plates of delicately woven hyphae. The peridium is smooth, not double, very 

 thin and fragile, and breaks easily into small particles at maturity, exposing the granular 

 contents. There is no sterile base. Originally there was only one species recognized, 

 A. album, described by Schweinitz from this state in 1822, but other tropical and austral 

 species have since been added. Long has described a genus Arachniopsis from Texas as 

 closely related to Arachnion (Mycologia 9: 272. 1917), but Lloyd, who saw the types, 

 thinks they are not different. Eolocotylon from Mexico and southern Texas is a 

 genus apparently related (Lloyd, Myc. Notes No. 21 : 254, pi. 73, figs. 5-8. 1906. 

 Also No. 22: 271. 1906). 



Literature 



Lloyd. The Genus Arachnion. Myc. Notes No. 21: 252. 1906; No. 46: 643. 1917. Also Myc. 



Notes No. 66: 1133. 1922. 

 Lloyd. The Lycoperdaceae of Australia, etc., p. 39. 1905. 



Long. Notes on New or Rare Species of Gasteromycetes. Mycologia 9: 271. 1917. 

 Saccardo. Syll. Fung. 7: 150. 1888. 



For other literature see p. 194. 



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