Part 65

General Information: P. sphinctrinus is recognised by the overall grey colouration and very distinct white fringe to the cap-margin.

P. campanulatus (Fries) Quélet which is said to be common is in fact infrequent and many records really refer to P. sphinctrinus. The word semiovatus means half ovate and refers to the shape of the cap in P. semiovatus. Sphinctrinus means banded, referring to the zoned cap of the fungus when it is partially dry.

Illustrations: P. semiovatus--LH 145; WD 77³. P. sphinctrinus--NB 41⁵; WD 78¹.

~Coprinus cinereus~ (Fries) S. F. Gray

Dung-heap ink-cap

Cap: width 20-40 mm. Stem: width 4-8 mm; length 50-100 mm.

Description:

Cap: oval then rapidly expanding, covered at first in a mass of dense, white or greyish woolly scales which break up into patches and finally leave the cap shiny, brownish grey at centre and striate and dark grey at the margin.

Stem: white, covered particularly towards the base with white, woolly scales, long, fragile, tapering upwards and at the base often elongated into a ‘tap root’ buried in the dung.

Gills: free, white but then rapidly dissolving into a black liquid.

Flesh: thin and whitish.

Spore-print: violaceous black.

Spores: medium sized, ellipsoid, smooth with a distinct germ-pore and 10-12 × 5-6 µm in size.

Facial cystidia: absent.

Marginal cystidia: inflated and large.

General Information: It is found on manure heaps, on straw dung and on silage heaps: very common throughout the year.

C. macrocephalus (Berkeley) Berkeley is very closely related to C. cinereus, but differs in having much larger spores over 12-15 × 7-9 µm, a long cap and a stem which lacks a rooting base.

Coprinus radiatus (Fries) S. F. Gray is smaller in stature and also differs in spore-size (11-14 × 6-7 µm). C. pseudoradiatus Kühner & Josserand is minute and has even smaller spores (7-9 × 4-5 µm). The dung-heap ink-cap has long been used by scientists in genetic studies, usually under the name of C. lagopus (Fries) Fries. However, this latter species, although similar, grows only on woodland detritus; it has narrower spores. The dung-heap ink-cap may be referred to in other books as C. fimetarius Fries or C. macrorhizus (Fries) Rea and whilst cinereus means grey referring to the colour, fimetarius means dung--from the habitat, and macrorhizus refers to the long rooting base found in some specimens.

Illustrations: LH 137; NB 41¹⁰; WD 81⁴.

The genus Coprinus--or Ink-caps

The genus Coprinus is easily recognised from all other agarics by the structure and development of the fruit-body. In the field, most species of the genus can be recognised by the gradual conversion of the gills, and often the cap tissue into a black liquid resembling ink--hence the name inky-caps. The conversion of the gills to an inky mass is called autodigestion and the process is complete within a few hours; this mechanism enables spores to be dispersed immediately they have ripened. Unlike other agarics the spores are not shot off into the spaces between the gills, but directly into the air. The gills are parallel-sided in Coprinus and not wedge-shaped as in more normal agarics, and in order to achieve spore dispersal the gills must disintegrate; Coprini are very specialised.

Coprinus is a large genus with over seventy members in the British Isles, many of which are strictly dung-loving. It is impossible to give more than one example in full here, for although many of the large species can be recognised on sight the smaller ones require the aid of a microscope. The interested student must therefore refer to more advanced texts, but in order to demonstrate the diversity of the Coprini and how they are classified the following key to the sections of Coprinus will be found useful.

1. Cap naked of any veil fragments, either smooth or covered in minute hairs 2

Cap covered when young by powdery or hairy veil, particles of which either may persist on the cap until maturity or may disappear quickly 3

2. Cap completely naked--group Nudi, e.g. C. miser (Karsten) Karsten

Cap with hairs giving it a frosted appearance--group Setulosi, e.g. C. ephemerus (Fries) Fries, C. pellucidus Karsten and C. bisporus J. Lange

3. Veil on the cap composed under the microscope of rounded cells giving the cap a floccose powdery appearance--group Vestiti, e.g. C. patouillardii Quélet, C. niveus (Fries) Fries and C. ephemeroides (Fries) Fries

Veil on the cap composed under the microscope of elongate cells, either like thin-hairs or strings of sausages 4