Daldinia "sp-IN02"

Daldinia "sp-IN02" is an ascomycete with 5 observations on iNaturalist as of April 24 2025 [1] . Observations are concentrated in the Appalachian Mountain area with one in Indiana. MycoMap reports one observation from New Brunswick, Canada [2] . Its seasonality between the 6 known records is June through October.

Description

Daldinia "sp-IN02" is an ascomycete that is most often reported on species of Betula with a brownish to brick red-brownish exterior color, white [3] (or light colored [4] ) internal rings, and a stubby [5] [6] or clustered [7] point of attachment. It reacts to KoH by releasing purple pigments [8] [9] slowly with photos documenting the color change at 1-2 minutes [10] , 3 minutes [11] , and 9 minutes [12] .

Similar Species

See below in Taxonomy section

Taxonomy

Pipsissewa notes in an iNaturalist journal post that:

"browsing the very large paper here: https://pmc.ncbi.nlm.nih.gov/articles/PMC3953824/

Purple pigmented KoH reported on Betulaceae or not in Northern Temperate areas include gelatinosa, loculata, loculatoides, petriniae, vernicosa

warmer climates in America include: grandis

moderate and warmer climates cosmopolitan: caldariorum

petriniae reported on "Alnus and other Betulaceae"

loculata on "Betula and other Betulaceae"

gelatinosa on "Betulaceae"

The two species names that come up in ITS blast searches are petriniae and decipiens. As luck would have it, there are a few of the species in question with their types sequenced. The current iNat sequence with the highest RiC ( https://www.inaturalist.org/observations/123167384 ) is 96.91%/96.58% similar to D decipiens, 94.74%/94.38% similar to loculatoides, 94.48% similar to vernicosa. I am admittedly confused as to why there were multiple entries for TYPE sequences unless the types have actually been sequenced and put into genbank multiple times. Anywho that narrows our list to petriniae, gelatinosa, caldariorum, loculata, and grandis.

D decipiens is reported to be European in the above paper

Ascospores 14-18(-19) × 6.5-10 μm. Known from temperate Northern Hemisphere

To my eye we need to check for dehiscence to divide into dehiscent (gelatinosa and petriniae) and non-dehiscent (grandis and loculata). Spore sizes will quickly rule out D caldariorum. If between petriniae and gelatinosum the asci are 200-230 μm in petriniae and 160-240 μm in gelatinosa. if between grandis and loculata, spore sizes will reportedly differentiate."

Ecology

Daldinia "sp-IN02" is reported or appears to grow on Betula [13] [14] [15] [16] and Thuja occidentalis [17].

References

information from https://www.inaturalist.org/journal/pipsissewa/105475-daldinia-sp-in02-sensu-s-d-russell