Common Names: derrumbes (landslide mushroom)
Cap: 2-9 cm broad. Obtusely
campanulate to convex with a decurved margin at first, becoming convex;
rarely plane with great age and often having either a small umbo or a
slight depression in the center. Margin often bluish,
translucent-striate halfway to the center portion of the cap and
hanging with fragile whitish veil remnants (appendiculate). Deep olive
black in young specimens, stronlgly hygrophanous, fading with age to a
dark reddish brown to chestnut brown near the disc and often darker
towards the margins. Margin incurved and often inrolled when young.
Surface smooth and slightly viscid to lubricous when moist, pellicle
thinly gelatinous but not usually separable. Flesh whitish to dingy
brown, moderately thick, and bruising bluish.
Gills: Attachment sinuate to adnate, close to subclose, and broad. Colour grayish to soot brown, with the edges remaining whitish.
Stem: 40-120 mm long by 2-10
mm thick. Mostly equal but often radicating into a long pseudorhiza.
Covered at first with a whitish layer of fibrils, which soon
deteriorates - revealing a more sordid brown, smooth surface
underneath. Upper regions of the stem characteristically adorned with
whitish fibrillose patches. Partial veil cortinate, whitish and copious
at first, but soon disappearing. Flesh stuffed and fibrous; bruising
bluish, whitish rhizomorphs (bluish when disturbed) present about the
base of the stem.
Microscopic features: Spores
dark purplish brown in deposit, subrhomboid to subellipsoid, 6-8 by 4-6
microns. Basidia 4-spored, occasionally 2-spored. Pleurocystidia
absent. Cheilocystidia 15-22 by 4.5-6 microns, fusoid with a flexuous
neck 1-2.5 microns broad.
Habit, habitat, and distribution:
Gregarious to cespitose, rarely solitary, found in the late spring and
summer on disturbed or cultivated grounds often devoid of herbaceous
plants. Preferring muddy orangish brown soils. First reported from near
Montgomery, Alabama, by Murrill in 1923 on sugarcane mulch, and not
redocumented from that locality since. P. caerulescens is widespread throughout central regions of Mexico, and also Venezuela and Brazil.