| Amanita
humboldtii Singer "Humboldt's Ringless Amanita"
BRIEF DESCRIPTION: The cap of Amanita humboldtii is usually free of volval remnants, 35 - 60 mm wide, subumbonate to depressed, with a strongly striate margin; it is dull fuscous brown or ranging from bark orange-brown to fuligineous in the center and orange-brown to medium dark brown in the outer part. Gills are free, close, white in side view, and about 5 mm broad, sometimes marginate and then having edge white or concolorous with pileus on the portion of the gills closest to the cap margin. There is no information on the short gills. The stem is 60 - 180 × 6 - 11 mm, entirely white or white on the lower half and pale orangish tan on the upper half, exannulate, and has a membranous sack-like volva at the base. Singer describes the volval sac as (for example) 20 × 12 mm high. The volval sack may be white, cinnamon, or orange; it is largely free from the stem. The spores measure (10.2-) 10.8 - 14.0 (-15.5) × (9.0-) 9.7 - 13.0 (-13.3) µm and are inamyloid, globose to subglobose or (infrequently) broadly ellipsoid. Clamps are rare or absent at bases of basidia. Amanita humboldtii is known from Andean Colombia, occurring with oak. Apparently, it is not frequently collected. One collection that might be attributable to this species has been sent me from Costa Rica. I have never seen fresh material of this species. Judging from Singer's original description, the species is apparently quite similar macroscopically to A. fuligineodisca Tulloss, Ovrebo & Halling macroscopically, but the two taxa can be distinguished microscopically. Based on the limited number of available collections known, A. humboldtii has larger spores and more layers of cells in its subhymenium. The closest relative of A. humboldtii may be A. pekeoides G. S. Ridl. of New Zealand. -- R. E. Tulloss Technical description. Last changed 16 August
2004. |