Nash, T.H., Ryan, B.D., Gries, C., Bungartz, F., (eds.) 2004. Lichen Flora of the Greater Sonoran Desert Region. Vol 2.

Life habit: lichenicolous, gall-inducing, non-lichenized Mycelium: hyaline, immersed in convex gall-like swellings of the host; galls: concolorous with the host thallus, mainly 0.5-1 mm in diam conidiophores: hyaline, macronematous, mononematous, developing below the surface of the galls conidiogenous cells: hyaline, aseptate, unbranched, arising from the surface of the galls, giving them a frosted appearance, monoblastic to 2-3-polyblastic, ampulliform to subcylindrical, basally swollen, tapering towards the apices, (15-)20-25(-30) x 6-8 µm, with conspicuous scars of 1.5-2 µm in diam. conidia: hyaline, simple, 0-1-septate, not catenate, dry, acrogenous, elongate clavate to subcylindrical, basally elongated and truncated (scar 1.5-2 µm in diam.), smooth, 15-25 x 5-6.5(-7) µm. Hosts: thalli of Peltigera species; in the Sonoran area on P. fibrillosa World distribution: Europe and North America Sonoran distribution: collected once in Chihuahua. Notes: Hawksworthiana peltigericola should not be confused with Refractohilum peltigerae (Keissl.) D. Hawksw., a species inducing similar galls on Peltigera, and with similar conidia. Refractohilum peltigerae is distinguished by annelidic conidiogenous cells, consistently aseptate conidia with a smaller length/width ratio, and longer and narrower conidiophores.