Observation 178345: Pisolithus Alb. & Schwein.

When: 2014-09-14

Collection location: Menlo Park, San Mateo Co, California, USA [Click for map]

Who: David Strehlow (dstrehlow)

No specimen available

This mushroom appeared in my Menlo Park yard in bare dirt at the edge of my lawn, and is different than any I’ve seen before. It has 3 equal lobes and is quite solid and dense. I assumed it was some kind of puffball but have not been able to identify it using online keys or photos. Regards – David

Proposed Names

61% (2)
Recognized by sight: The seed-like structures on the inside are called peridioles.
Used references: Arora, Mushrooms Demystified. This is a mycorrhizal fungus, and requires a nearby host tree, usually a pine, oak, or eucalyptus. Which is it, David?

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Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
Most likely host is
By: Daniel B. Wheeler (Tuberale)
2014-09-16 01:14:35 CDT (-0400)

either pine, oak, sycamore or birch. Pisolithus associates with all these. Will need to research maytens, privet and ginkgo, though, as these trees are uncommon in my area.

Mycorrhizal fungi like Pisolithus can extend at least twice the height of the tree away from the base. In the case of oak, which may be much broader than high, perhaps the same based on how broad the tree is.

NATS (North American Truffling Society) once located a Tuber gibbosum fruiting nearly 200 feet distant from an isolated 150-foot-tall Douglas-fir. Tuber gibbosum is an obligate mycorrhizae of Douglas-fir. The truffle was found in the bottom of recently plowed furrow.

details about nearby trees
By: David Strehlow (dstrehlow)
2014-09-15 09:43:59 CDT (-0400)

Pisolithus looks likely but there are no nearby oaks, pines or eucalypts. The nearest trees are a privet i cut down in january (13ft), a maytens (13ft) and a birch (15ft). There is a sycamore (25ft) and the nearest oak is across the street (86ft). Yesterday a second example appeared in my back yard. The nearest trees to the second example are an apple tree (9ft), a ginkgo (13ft) and a maytens (13ft). The nearest pine is in the neighbor’s yeard (58ft). Any thoughts as to which of these is the most likely associate tree?

Created: 2014-09-14 17:55:00 CDT (-0400)
Last modified: 2014-09-15 02:16:06 CDT (-0400)
Viewed: 42 times, last viewed: 2017-06-30 07:33:33 CDT (-0400)
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