Observation 18642: Amanita Pers.

When: 2009-02-18

Collection location: San Geronimo, Marin Co., California, USA [Click for map]

Who: Ron Pastorino (Ronpast)

Specimen available

Single specimen found under live oak, somewhat waterlogged. White cap 6.3 cm across,no warts and no sign of an annulus. White spores, not amyloid, and approx. 9.4 X 6.5 microns. Some knife wounds on the base and stem but it does have a volva with a slightly enlarged base.



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Ocreata was my first choice but….
By: Ron Pastorino (Ronpast)
2009-02-22 09:06:00 PST (-0800)
It would seem to have two strikes against it. There were plenty of spores dropped and they did not darken in Melzers, which if I recall correctly is usually a quick reaction with this species. Also, the specimen was growing fairly well protected and I didn’t see any annulus or annulus fragments around it. However, it can’t be ruled out on that point alone. I don’t recall if the stipe was chambered or not but it dried up rather uniformly. The spores seemed boringly Amanita-like and maybe slightly too elliptical for ocreata.
cut it in half…
By: Debbie Viess (amanitarita)
2009-02-20 16:56:42 PST (-0800)

check to see if the stipe is solid or with discrete, hollow chambers (I’ll post an illustration of what i mean). if so, could be an ocreata sans annulus; recheck for an amyloid rxn.

if base is bulbous, only section phalloides (ie ocreata) would have a membranous volva (apparent in your photo at top of bulb), altho a white phase section amanita is a possibility, since your specimen is so rain-beat and details are obscured. can’t be section vaginata (ie velosa) with a bulb.

spore shape or photo?

under live oak, with the general gestalt and timing, ocreata is the most likely choice.

Created: 2009-02-19 21:26:55 PST (-0800)
Last modified: 2009-02-19 21:26:55 PST (-0800)
Viewed: 68 times, last viewed: 2018-09-08 08:59:58 PDT (-0700)