When: 2008-11-16

Collection location: Southeast Portland, Multnomah Co., Oregon, USA [Click for map]

Who: Daniel B. Wheeler (Tuberale)

Specimen available

Found near (but not directly under a branch) of Douglas fir in my neighborhood. Specimen was slightly erumpent (above soil surface), located near the narrow-leaved plantain in a parking strip, about 20 feet or so from the Douglas fir. The exposed area is dark brown to bluish-black, with some white bloom on the peridium as dug. Most rhizomorphs (root-like structures) were at base of clump of 6 Rhizopogon parksii, all grown together. Rhizopogon nests like this are fairly common. Basing my identification on the staining of the peridium, and the frequency of collections submitted to NATS for identification. Rhizopogon parksii is the most frequently collected of all Rhizopogons in Oregon, and the most frequently collected species in Oregon, with over 100 collections currently in the OSU herbarium. This collection will be on its way there as soon as I dry it.

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Proposed Names

86% (1)
Recognized by sight
Used references: Aurora’s Mushrooms Demystified, NATS Color truffle cards

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Add Comment
By: Daniel B. Wheeler (Tuberale)
2008-11-17 04:00:14 EET (+0200)

this collection may well have been a result of heavy rainfall in Portland on Nov. 11-13, which produced at least 5 inches of rain. Rhizopogons are known to mature very quickly after their host tree has become supersaturated with water, and can spare additional available water for the fungus to produce sporocarps. Rhizopogons are basically spore-delivery systems for small animals. A single sporocarp, according to Dr. James Trappe, contains sufficient spores to inoculate several million seedling trees at 10,000 spores per tree, or enough to colonize at least a square mile (640 acres) of Douglas fir planted at 600 trees/acre. It also is a major source of food for California Red-backed voles, Creeping voles, Northern Flying squirrels, and other mycophagous animals.