The Genus Armillaria in Western Washington

Abstract

The genus Armillaria is well represented in western Washington, some species occurring very abundantly, especially Armillaria mellea. The genus was first recognized by Fries in 1821 (4) as a tribe under Agaricus but later it was discarded by both Ricken and Lange who distributed the species among other genera. In 1914, Ricken (23) in his reorganization of the genus, transferred seven species, including Armillaria mrellea, to the genus Clitocybe, nine to Tricholoma, three to Collybia, and four to Pleurotus. In 1914, Lange (18) in general followed Ricken's interpretation of the genus but placed Armillaria rmellea in the genus Lepiota. In America most mycologists have not accepted this abolition of the genus for, although admitting it to be a more or less heterogenous group, they believe that transferring the various species to other genera does not solve the problem. Peck (21), in 1890, describes eight species which, at that time, were known in the United States. Murrill (20), in 1914, listed 14 species, two of which were tropical. He only included three of Peck's eight and left the others unmentioned. Kauffman (13), in 1918, described six species, two of which, A. dryina and A. corticata, had previously been placed in the genus Pleurotus. Again, in 1922, he (15) consolidated the genus for the United States and listed 28 species, eleven of which have been reported for Washington and Oregon, and two of which have later, due to the work of Zeller, been proven to be synonymous, A. ponderosa and A. arenicola (27). Since that time five additional species have been reported by Zeller and Kauffman for Washington and Oregon. In the present article, which is the fourth of a series on the Agaricacae of Western Washington (10, 11, 12), fifteen species are reported. The writer has two main objects in view in this article: to bring