Hymenopellis radicata
Description
Hymenopellis radicata is a widespread agaric readily identified by its deeply rooted stalk (stipe). It is one of the early-fruiting wood rotters. The cap is medium to large, flat, grayish or yellowish-brown and streaked, with a central hump, and has a size of between 5 and 12.5 cm. The surface of the cap is sticky or slimy when moist, with the underside displaying wide white gills, or lamellae. The brittle stalk tapers at both ends and is nearly white above to brown below the soil.
The stem grows into a long deeply rooting tap root until it touches a piece of wood. This may grow up to 20 cm in length in some specimens.
Hymenopellis radicata is generally regarded as an edible mushroom, but it is not highly rated and, because it rarely occurs in any great numbers, not worthwhile.
Common names: The Deep Root Mushroom, The Rooting Shank.
Mushroom Identification
Cap
3-10 cm, initially convex, then flattened-convex, finally flat, with wide low and obtuse umbo; thin margin, regular, acute, smooth, a little wavy; smooth cuticle when young, soon later radially wrinkled, glabrous, opaque with dry weather, viscous when humid; of pale brown, hazel, whitish at times, darker at the center, color.
Hymenium
Spaced gills, adnate or rounded, ventricose, wide, interspersed with numerous lamellulae of various lengths; the color is white, the thread is entire, and just stains brown when ripe.
Stem
6-15(20) x 0,5-1,5 cm, slender, long, cylindrical, with the enlarged base continuing in the soil under the form of root for several centimeters, rigid, fibrous, tough, full, at times twisted; surface finely floccose, longitudinally fibrillar, white at the apex, darkens gradually towards the base, where it has a coloration more or less similar to that of the cap.
Flesh
Exiguous, soft, watery, fibrous in the stem, off-white. Feeble smell, slightly fruited, sweet taste.
Habitat
It grows in summer and even in late autumn, on rotting stumps or woody residues of broad-leaved trees, especially of beech.
Spore Print
White.
Microscopy
widely ellipsoidal spores, elongated-ovoidal, smooth, guttulous, 15-18 x 8-10 µm. Basidia: cylindrical, clavate, tetrasporic, with clamp connections, 45-55 x 10-15 µm. Cheilocystidia: clavate, ventricose, smooth, 60-110 × 12-35 µm. Pleurocystidia: widely clavate, widely rounded, truncated at the apex, 60-120 × 22-35 µm.
Look-Alikes
Hydropus subalpinus
The rare mushroom, lignicolous too, with smaller dimensions, the cuticle of the cap not wrinkled and the umbo is more acute and the stem is not rooting.
Oudemansiella longipes
Has velvety stem and cap.
Pluteus genus
But a spore print (spores are pink in mass for Pluteus) would resolve any doubt.
History
When British botanist/mycologist Richard Relhan (1754 - 1823) described this mushroom in 1785 he named it Agaricus radicatus. (Most of the gilled fungi were initially placed in a giant Agaricus genus, most of whose contents have since been redistributed to many other genera.) Being something of an oddball in terms of appearance and growth habit, it is perhaps unsurprising that there has been much debate about where this species sits in the taxonomic system. Rooting Shank has therefore acquired many other scientific names over the past 230 years. Its recent scientific name Xerula radicata dates from a 1995 publication by the German mycologist Heinrich Dörfelt (born 1940); however, in 2010 American mycologist Ron Petersen (b. 1934) circumscribed the new genus Hymenopellis with Hymenopellis radicata as the type species.
Synonyms of Hymenopellis radicata include Agaricus radicatus Relhan, Gymnopus radicatus (Relhan) Gray, Collybia radicans P. Kumm., Collybia radicata (Relhan) Quél., Mucidula radicata (Relhan) Boursier, Oudemansiella radicata (Relhan) Singer, Xerula radicata var. alba Dörfelt, Oudemansiella radicata var. marginata (Konrad & Maubl.) Bon & Dennis Oudemansiella radicata (Relhan ex Fr.) Singer, and Collybia radicata (Relhan ex Fr.) Quél. and Xerula radicata (Relhan: Fr.) Dörfelt.
The name of the species comes from the Latin “radicatus” = it has rooted, I have roots.
Photo sources:
Photo 1 - Author: Lukas from London, England (CC BY-SA 2.0)
Photo 2 - Author: Jerzy Opioła (CC BY-SA 4.0)
Photo 3 - Author: Jerzy Opioła (CC BY-SA 4.0)
Photo 4 - Author: Jerzy Opioła (CC BY-SA 3.0)
