Created: 2008-03-01 17:37:36

By: Michael Wood (mykoweb)

Summary: Hysterangium or Trappea?

Comment: Definitely not a Hymenogaster, which does not have an olivaceous gleba. These are either Hysterangium or Trappea. Hysterangiums are much more common, in fact a Hysterangium (we used to call it H. seperabile, but I think that was a misnomer) is one of the really common truffeloid fungi under our local live oaks. Mature Hysterangiums have a VERY pungent odor.
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Bote Hysterangium and Trappea commonly have the olivaceous green gleba. Trappea was segregated from Hysterangium by Castellano based on peridial features and the smooth spores of Trappea versus roughened of Hysterangium. Without scoping the collection, I would lean towards Hysterangium, since T. darkeri is associated with conifers and Hysterangiums are very common in the Bay Area with live oak.
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References:
Castellano, M.A. (1990). The new genus Trappea (Basidiomycotina, Hysterangiaceae), a segregate from Hysterangium. Mycotaxon 38: 1-9.
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Zeller, S.M. & Dodge, C.W. (1929). Hysterangium in North America. Ann. Missouri Bot. Gard. 16: 83-128.
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And if you are intereted in the phylogenetics of the gomphoid/phalloid clase:
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Hosaka, K. & others. (2006). Molecular phylogenetics of the gomphoid-phalloid fungi with an establishment of the new subclass Phallomycetidae and two new orders. Mycologia 98: 949-959.
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That puts Hysterangium in the Hysterangiales and Trappea in the Phalalles.