Identification of the Larger Fungi

by Roy Watling

[Larger illustration]

5. Take out a small block of tissue T as indicated in the figure ([fig. 1]). Mount immediately and repeat as in [3]. This will allow the outer layer of the cap to be more clearly seen ([fig. 7]A-C) and also the structure of the flesh ([fig. 10]). The latter may be composed of a mixture of filaments and ‘packets’ or ‘nests’ of rounded cells (i.e. heteromerous), or of filaments, only some of which may be inflated (i.e. homoiomerous); but when individual cells are swollen they never form distinct groups. By very similar techniques it is possible to show that the more woody fungi can have flesh composed of one of four types of cells (Corner, 1932): these types depend on whether distinctly thickened cells ([plate 47]) are present with the actively growing hyphae or not ([pp. 140-150]), whether hyphae are present which bind groups of hyphae together, etc. ([plate 46]).

6. Remove stem along line CD and cut out small blocks of tissue as indicated (U, V and W). Mount immediately and examine as in [paragraph 3], for cystidia, etc. (see [fig. 3]).

Whilst all these sections are being cut and processed a second fruit-body, if available, should be set to drop spores; this is done by cutting off the cap from the stem and placing it either entirely or in part, and with gill-edges down, on a slide in a tin.

7. Z is a ‘scalp’ of a cap; a thin sliver from the cap is placed on a slide in a drop of water (modified with washing-up liquid, etc. as above). After placing a cover-slip over the tissue it is tapped gently; this will show if the cap is composed of globose to elliptic elements or if it is composed of strictly filamentous units ([figs. 6]A & B). Care must be taken not to reverse the section when transferring it to the mountant, either by turning the scalpel or by allowing the surface tension of the liquid to pull the section upside down. The construction of any veil fragments will also be seen in this mount, and if a loose covering of veil is present this should be removed before observation so that it does not obscure the fundamental structures.

8. Examine the stipe of the fruit-body used above under a low power or with a dissecting microscope in order to ascertain whether there are any remains of veil and/or vegetative mycelium. If found, mount immediately in the solution containing iodine mentioned above and examine.

Of course it is difficult to carry out the above system the first time and be successful in seeing everything, indeed in being able to cut all the sections 1-8. Practice makes perfect, so why not practise with a ¹⁄₄ lb of mushrooms from the grocer before the autumn season starts. In this way you will have overcome the difficulties without having to experiment with your collections.

CHARACTERISTICS FOR THE IDENTIFICATION OF HIGHER FUNGI WITH CAPS
Locality		G. Ref.		Date
Habitat notes		soil type		pH
		vegetational community
		solitary; in troops or rings
Draw or preferably paint exterior and vertical section of fruit-body
MACROSCOPIC CHARACTERS
CAP
	General characters:
	diameter		shape		consistency
	colour:		when immature		when mature
			when wet		when dry
	Surface
	dry, moist, greasy, viscid, glutinous, peeling easily or not, smooth, matt, polished, irregularly roughened, downy, velvety, scaly, shaggy
	Margin
	regular, wavy			incurved or not
	smooth, rough, furrowed			striate or not
	Veil, if present
	colour			abundance or scarcity
	distribution at margin, whether appendiculate or dentate
	consistency, whether filamentous, membranous
GILLS, or pores or teeth etc.
	remote, free, adnate, adnexed, emarginate, subdecurrent, decurrent
	crowded or distant			distinctly formed or not
	shape			interveined or not
	easily separable from the cap-tissue or not
	consistency (whether brittle, pliable, fleshy or waxy)
	thickness			width
	colour:		when immature		at maturity
	number of different lengths or number of layers
	obvious features of gill-edge, tube-edge, e.g. colour, consistency
STEM
	central, eccentric or lacking				shape
	dimensions: length			thickness
	hollow or not
	colour:		when immature		when mature
	consistency (whether fleshy, stringy, cartilaginous, leathery or woody)
	surface characters (whether fibrillose, dry, viscid, scaly or smooth)
	characters of stem-base
	Veil, if present	characters
	Volva, if present	characters
	Ring, if present
	whether single or double			whether membranous or filamentous
	whether persistent, fugacious or mobile			whether thick or thin
	whether apical, median or basal
FLESH
	colour in cap:		when wet		when dry
	colour in stem:		when wet		when dry
	colour changes if any when exposed to air
	presence or absence of milk-like or coloured fluid
	(note: colour when exuded on fruit-body immediately and after some time and when dabbed on to aclean cloth or paper handkerchief and exposed to the air).
SMELL	before and after cutting			—relate to a commonevery day odour
MICROSCOPIC CHARACTERS
BASIDIOSPORES
	colour in mass			colour under microscope.
	shape		size	type of ornamentation, if any
	size and shape of germ-pore, if present
	iodine reaction of spore-mass:—blue-black to dark violet (amyloid); red-purple
	(dextrinoid); yellow-brown or brown (non-amyloid)
BASIDIA		number of sterigmata
CAP-FLESH		type of constituent cells
GILL-TISSUE		type and arrangement of cells between adjacent hymenial faces
CAP-SURFACE		type of cells composing the outermost layer—whether filaments or rounded cells
STERILE CELLS—CYSTIDIA
	presence or absence of sterile cells:—
	on gill-edge			on gill-margin
	on cap			on stem
	shape, estimation of size, thick or thin-walled, hyaline or not
	types of ornamentation, etc.