Arthromyces, T. J. Baroni & Lodge, 2007

Key to Arthromyces View in CoL View at ENA and Blastosporella in the Neotropics, insect associated taxa arising from aggregated masses of insect faecal pellets

1. Pileus mostly plane, up to 40 mm broad, brown, translucent-striate, hygrophanous, glabrous and not producing arthroconidia on the pileus or stipe (currently known only from Brazil and Guyana) .............................................................................. A. glabriceps

- Pileus variously shaped, but always producing dark brown or fuscous black powdery conidia........................................................2

2. Pileus truncate-convex and strongly zonate at first with gray and dark brown bands, soon deeply depressed over disc producing a well-defined rim around the disc with the depression filled with powdery soot-brown blastospores produced by inflated hyphal end cells on the pileus, blastospores globose and strongly tuberculate ornamented ( Colombia and Dominican Republic) ............... ........................................................................................................................................................................... Blastosporella zonata

- Pileus not strongly zonate nor depressed with well-defined rim around the disc, pileus variously shaped and producing dark gray or grayish-brown arthroconidia in chains of disarticulating end cells on the pileus and in one species also the stipe......................3

3. Pileus with well-developed, thick, pale grayish-cream colored marginal roll at first, which turns olivaceous-brown and powderypulverulent from production of long chains (10–20 cells) of smooth walled, dark brown arthroconidia, cheilocystidia narrowly clavate or cylindrical-capitate and not encrusted ( Colombia) ................................................................... Arthromyces pulverulentus

- Pileus lacking well-developed, thick marginal roll, arthroconidia verrucose or punctate roughened, typically in chains of less than 10 cells, cheilocystidia with resin-encrusted apices ..........................................................................................................................4.

4. Pileus up to 55 mm broad, convex and grayish-yellow to clay color, margin translucent-striate at first, pileus disc area soon developing dark grayish-brown powdery arthroconidia and production of arthroconidia spreading towards the margin, arthroconidia dark brown and finely punctate ornamented over the outer walls ( Belize and Florida, USA) ......................... Arthromyces matolae

- Pileus up to 15 mm broad, ± convex, typically with broadly truncate disc which is strongly depressed with age, pileus margin strongly inrolled, entire pileus opaque; pileus and stipe densely covered with short chains of powdery dark brown verrucose ornamented arthroconidia ( Dominican Republic, Puerto Rico) ................................................................... Arthromyces claviformis