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Species Information
Summary: Features include a saucer-shaped to expanded fruitbody with violet upper surface and pale violaceous scurfy lower surface, absent stem, growth on burned places and occasionally elsewhere on the ground, and finely warted mature spores. There have been difficulties interpreting P. violacea Pers. and P. praetervisa Bres.: according to Pfister(5), "Peziza praetervisa has lightly ornamented spores as described by Seaver for P. violacea. The spores of P. violacea are completely smooth. Though P. violacea exists in North America, it is infrequently collected. Most collections under that name are P. praetervisa." The name Peziza praetervisa Bres. in the sense of Dennis is used for this species with lightly ornamented spores, as the sense of Bresadola may correspond to Peziza petersii Berk. & Curt. Because of these difficulties the name Peziza subviolacea Svrcek has been proposed for P. praetervisa Bres. sensu Dennis. In effect, one view (that of Dennis(1), Pfister(5), Breitenbach(1)) uses the name P. praetervisa Bres. for the commoner species in North America that has finely warted mature spores and P. violacea Pers. for the one with smooth mature spores, and the other uses the name Peziza violacea Pers.: Fr. or Peziza subviolacea Svrcek for the commoner species in North America with finely warted spores and Peziza sublilacina Svrcek for the one with smooth spores. We follow Michael Beug in avoiding the name Peziza violacea which is ambiguous. We use the name Peziza praetervisa for the commoner species with finely warted spores and Peziza sublilacina Svrcek for the one with smooth spores. According to Beug(3), P. praetervisa has spores with two oil drops and Peziza sublilacina has spores with no oil drops.
Peziza praetervisa has been found at least in OR, ID, also AB, CO, (according to Larsen(1) who also list P. violacea for British Columbia, Washington, Oregon, and Idaho). There are collections under the name Peziza praetervisa Bres. for BC at Pacific Forestry Centre and University of British Columbia. It has been reported from WA by Andrew Parker, pers. comm.
Upper surface: 1-6cm, "rather circular and saucer-shaped when young, then expanded and irregularly deformed"; spore-bearing upper surface light to dark violet, also brown-violet, smooth, (Breitenbach), up to 3cm, cup-shaped then expanded; upper surface violet, sometimes with brownish tints, (Dennis)
Underside: lighter in color than upper surface; finely furfuraceous, (Breitenbach), pale violaceous; minutely scurfy, (Dennis)
Stem: none (Breitenbach)
Microscopic: spores 12-14(15) x 6-8 microns, elliptic, with fine warts when mature, colorless, with 2 drops; asci 8-spored, 170-250 x 9-12 microns, positive reaction to iodine; paraphyses weakly clavate, 1.5-2.5 microns, slightly curved, tips with brown-violet contents, (Breitenbach), spores 11-13(15) x 6-8 microns, finely warted, with 2 oil droplets; asci about 250 x 10 microns; paraphyses "slightly clavate, mostly slightly curved at the tip, which is filled with purplish granules", (Dennis), spores 11-15 x 6-8 microns, ornamented with low warts, containing two oil droplets, (Trudell)
Habitat / Range
single or gregarious, "often several individuals fused together to form a cluster", on burned places, principally in the first 12 months after fire, "also occurring in masses on sandy forest paths without any relationship to charred wood", (Breitenbach), often clustered, on burned ground in woods and heaths, occasionally on sawdust; October to May, (Dennis)
Similar Species
Peziza lobulata (Velenovsky) Svrcek (=Peziza violacea Persoon sensu Dennis) is closely related to P. praetervisa - it has spores 13-15.5 x 7-8.5 microns and curved paraphyses (Beug(3)). While Beug(3) says that it is not associated with burn sites, Svrcek(1) examined Velenovsky''s material of the synonym Plicaria adusta from burnt soil, giving spore size 13-14 x 7-8 microns. A collection of Peziza lobulata from Washington was used in the molecular study Hansen, K.(5). There is a Tennessee collection on burnt soil at the University of Illinois "99% match with LSU to Peziza lobulata in GenBank! 98% match with ITS to Peziza lobulata in GenBank!" but the material was in such poor collection that it was difficult to see ascomata. All other MyCoPortal entries are from Europe. Hansen, L.(1) says the fruitbodies are disc-shaped to cup-shaped and 0.5-3cm across, the hymenium violet, the exterior bluish gray and bald, the habitat newly burnt ground, the spores 13-15.5 x 7-8.5 microns, smooth without guttules, and the paraphyses curved, with violaceous brown contents. |See also SIMILAR section of Peziza domiciliana and Peziza sublilacina.
