aprile
Early fruiting period

aprilis
Of or pertaining to the month of April

aquifluus
Water, fluid (clear latex)

aquosa
Very watery (viscid cap)

Arachnion
Small spider web

Arachnopeziza
Spider Peziza

araiospora
Thin spore

Araneosa, araneosum
Full of spiders webs

arbustivus
Pertaining to plantations

arbuticola
Arbutus-dwelling (Arbutus menziesii=mandrone)

arcangeliana
Pertaining to Arcangel

Arcangeliella
Diminutive of Arcangel

archeri
William Archer (1830-1897), Irish natural scientist

arctostaphylos
Growing with Arctostaphylos uva-ursi

arcuata
Curved

arcularius
Pertaining to a casket

Arcyria
Pertaining to a net (capillitium a loose network of threads)

ardosiacum
Pertaining to water

arduennensis
The Arduenn region (around Ardenne in Belgium)

aremoricus
Pertaining to northern Gaul

arenaria, arenarium, arenarius
Pertaining to sand

arenatus
Sandy

arenicola
Sand dweller

areolatum, areolatus
Divided into small patches, areolate, cracked

areus
Mistake for "aereus"

argentatus
Silver plated

argenteum, argenteus
Silvery

argentinus
Somewhat silvery

argillacea, argillaceus
Clay colored

argillaceifolius
Clay colored (dingy yellowish-brown) gills

argillaceifolius var. megacarpus
Clay colored gills; large fruiting body

argutus
Sharp

argyraceum, argyraceus
Silver colored

arhizus
Without roots

ari-triphylli
From host Arisaema triphyllum (Jack-in-the-Pulpit)

arizonicum
Arizona

arkansana
Arkansas

armeniaca, armeniacum, armeniacus
Apricot colored

Armillaria
Pertaining to a ring

Armillariella
Diminutive of Armillaria