Gills: adnate, whitish but soon pale honey and finally rusty honey.
Spore-print: rust-brown.
Spores: long, ellipsoid or slightly amygdaliform, golden brown under the microscope with large germ-pore and 12-14 × 7-8 µm in size.
Facial cystidia: absent.
Marginal cystidia: capitate.
General Information: C. dunensis differs from C. tenera in its dull colours (see [p. 116]) and habitat preferences. Conocybe dunensis, Stropharia coronilla, the two species of Psathyrella are all dull-coloured. However, in the sand-dunes colourful agarics are also found. The most common is Hygrocybe conicoides (P. D. Orton) Orton & Watling; Laccaria maritima (Theodowicz) Moser is indeed an unusual but rewarding find. ‘Lac’ as in Laccaria is a red-brown resinous substrate produced by the lac-insect and resembles the cap colour of many species of the genus, including L. maritima, L. laccata and L. proxima (see [p. 86]). All these fungi were formerly placed in Clitocybe, but they differ in the warted or spiny spores which at maturity give the rather thick gills the appearance of being heavily talced. L. maritima can be distinguished from all other species of Laccaria by the elongated spores which are minutely spiny and not strongly warted as in L. laccata. Hygrocybe conicoides (P. D. Orton) Orton & Watling has a conical to conico-convex, acutely umbonate cap with wavy-lobed margin; it is scarlet or cherry-red, discolouring blackish with age or on bruising. The gills are at first chrome-yellow then become flushed red and the stem is yellow or greenish lemon becoming streaky blackish after handling. The spores are 10-13 × 4-5 µm in size and slightly French bean-shaped. It can be readily distinguished from close relatives, e.g. H. conica (Fries) Kummer by the gills soon turning reddish, the reddish cap and the narrow spores.
(viii) Subterranean fungi
General notes
The adaptive habit of growing completely submerged beneath the surface of the ground has developed in all the major groups of fungi. Thus the simplest form related to the common bread-mould have taken up the character just as certain relatives of the disc-fungi (discomycetes) and of the flask-fungi (pyrenomycetes). In the higher fungi in several foreign countries even agarics, polypores and stinkhorns have become hypogeous, but in this country we have a very depauparate flora composed of some twenty-eight species of false (Basidiomycete) truffle. The following key may assist in identifying the different groups of hypogeous fungi for some of these species are of commercial value and includes the French or Perigord truffle, Tuber melanospermum Vittadini which is used as a constituent of Pâté de Foie Gras, and many of the fungi used as poor quality substitutes. There is a long folk-history surrounding truffles and they have been utilised in the production of aphrodisiacs for centuries. Seeking them out was a difficulty and has been overcome in different countries in different ways. Thus in continental Europe, pigs have been used to sniff them out but on finding them the pigs cannot eat the truffles because of a ring placed through their nose. In Dorset a particular breed of dog was developed to do the same job—the Dorset hounds.
A simple key would read as follows:—