jonaleef's Identifications

Rodent digs found throughout the area exclusively under chamise. Manzanita also present, and interior live oak within 100 feet, but digs were only under chamise. Digging revealed that the mycelial mat that truffles were found in and smelled the same dissipated with distance from chamise. Melanogaster also mixed in and more abundant. Parts of the mycelial mat smelled like Melanogaster and parts smelled like these -- distinctly of oil paint. Woodrat nest about 8 feet away.

In canyon wall and soil clinging to underside of boulder with roots nearby, presumably belonging to the Quercus chrysolepis uphill. Alder and bay laurel also nearby, alder being downhill near the stream

These were first spotted by @kueda in https://www.inaturalist.org/observations/197187713, on Lophostemon confertus in a parking lot (!!). I collected them a few days later, and they had already begun to shrivel up (compare photo 1 to photo 2 of younger specimens)

Macro Summary:
Pileus: 2-5mm, convex to plano-concave with age, dimidate when viewed from above; cream to pale buff when young, cinnamon brown in age; surface dry, rugulose-tomentose; margin scalloped, tomentose and with pale cream edge when young, pleated with age; Lamellae: cream to pale buff when young, cinnamon brown in age; adnexed to narrowly adnate, frosted with shiny brown spores, distinct pale margin in older specimens, wrinkling in age; lamellulae present; Stipe: Size: 0.5–2 mm, central, slightly enlarged at base; cream to pale buff when young, browning in age (but paler than pileus); pruinose to tomentose, texture solid, no ring or volva present; Odor:indistinct; did not taste; Milk: None observed; Chemical changes: In 3% KOH, it was the stipe that turned blackish to very dark brown. There was some yellowish brown coloration in the liquid, but hard to say if those were just dilute spores?? Slides of a section of lamellae in KOH were not full of pigment. Apparently Gymnopilus and Pleuroflammula contain yellow styrylpyrone pigments that leach out in 3% KOH, so perhaps those two genus are ruled out?.

Micro Summary:
Spores (6.6) 6.9 - 8.5 (8.8) × (4.5) 4.6 - 6.2 (6.5) µm; Q = (1.1) 1.3 - 1.6 (1.7) ; N = 30; Me = 7.7 × 5.4 µm ; Qe = 1.4
Ellipsoid to ovate, ( including many banana shaped collapsed spores); smooth (some spores with granular looking contents possibly minutely punctate), some appear slightly truncate (apical pore or hilar plage?);
Cystidia: cheilocystidia cylindrio-clavate, perhaps sub-capitulate. Clamp connection: present in pileus trama

References reviewed:
Horak Pleuroflammula 1978 https://archive.org/details/persoonia532145/page/440/mode/2up. I could not find a copy of Rees Mycological Research 1999 on small statured Gymnopilus https://www.sciencedirect.com/science/article/abs/pii/S0953756208602932?via%3Dihub but there other hand there is Rees 1996 thesis https://unsworks.unsw.edu.au/entities/publication/9fa04806-e133-4c5f-b72a-d0339bca9d73/full with a long discussion of Gymnopilus species, as well as some criteria to distinguish them from Phaeocollybia, Pyrrhoglossum and Galerina (includes description of G. eucalyptorum). Also consulted https://www.alpental.com/psms/ddd/Hymenogastraceae/Gymnopilus.htm
Ed to add more refs:
Petersen et al, Cladistics, 2010 https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1096-0031.2009.00279.x
Metheny et al, Mycol Progress, 2006 http://mathenylab.utk.edu/Site/Publications_files/Matheny_Bougher_2006.pdf