?? × ?? μm, dominantly 4- and occasionally 2-sterigmate, with sterigmata up to at least 5.5 × 1.5 μm; clamps present (plenitude not known).
On pileus: filamentous undifferentiated hyphae 2.5 - 8.5 μm wide, branching, anastomosing, plentiful, dominating at upper surface, with wall ocassionally up to 0.5 μm thick, with some terminal segments slightly inflated; inflated cells plentiful to locally dominant, subfusiform to clavate to broadly clavate to ellipsoid (up to 80 × 42 μm) to globose or subglobose (e.g., 59 × 46 μm), terminal singly or in chains of up to at least three, occasionally with walls up to 0.8 μm thick; vascular hyphae not observed; clamps difficult to find. On stipe base: ??.
[59/2/2] (10.0-) 10.1 - 13.3 (-15.3) × (6.3-) 6.8 - 8.9 (-10.4) μm, (L = 10.8 - 12.2 μm; L’ = 11.5 μm; W = 7.2 - 8.1 μm; W’ = 7.7 μm; Q = (1.29-) 1.39 - 1.59 (-1.65); Q = 1.49 - 1.50; Q’ = 1.50), hyaline, colorless, thin-walled, smooth, inamyloid, ellipsoid to (occasionally) elongate, infrequently broadly ellipsoid, sometimes expanded at one end, sometimes constricted, sometimes expanded at one end, adaxially flattened; apiculus sublateral, cylindric; contents dominantly monoguttulate ("oil drop" type), occasionally multiguttulate or granular; cream? or white or whitish in deposit.
Solitary. On gravelly soil in the "fog belt" or in unspecified soils and associated in both cases with young or mature Pinus muricata, Quercus, and Arctostaphylos.
U.S.A.: CALIFORNIA—Sta. Barbara Co. - Channel Islands Nat. Pk., Sta. Cruz Isl., Los Pinos del Sur ridge [33°59'01" N/ 119°36'00" W], 16.i.2002 Lisa Grubisha 1045 (UCB ?? as "A. cf. muscaria var. formosa” and “AM23” in (Geml et al. 2008)); Channel Islands Nat. Pk., Sta. Cruz Isl., first ridge with native P. muricata on tr. from Prisoner’s Harbor to Pelican Bay [33°59'01" N/ 119°49'00" W], 17.i.2002 Lisa Grubisha 1066 (UCB ??, as "A. cf. muscaria" and "AM24" in (Geml et al., 2008)).
This species is represented by Clade V of Geml et al. (2008: Fig. 1). In the phylogeny resulting from the research reported in that paper, this entity is a sister taxon to A. muscaria var. persicina—a similarly pigmented taxon with known range restricted to the southeastern United States.
The following figure provides a sporograph comparison between the sister taxa:
Much of the hymenium of Grubisha 1045 is immature and sterile. In Grubisha 1066, the subhymenium is too badly preserved to permit the location of clamp connections (to date). Grubisha 1066 is not associated with field notes.
—R. E. Tulloss, J. Geml, and L. Grubisha
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Tulloss, Geml, & Grubisha
Spore data for collections provisionally identified as: Amanita sp-LG1045 Tulloss, Geml, & Grubisha
Each spore data set is intended to comprise a set of measurements from a single specimen made by a single observer;
and explanations prepared for this site talk about specimen-observer pairs associated with each data set.
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(which may be valuable for instructional purposes, for example) and may obscure instances in which
a single collection inadvertently contains a mixture of taxa.