IIARDWICKE'S SCIENCE-GOSSIP. 



255 



apply too much pressure, in fact the majority do not 

 require any pressure at all ; with respect to the fleshy 

 fungi, my experience has been large, but success 

 small, nevertheless it can be clone, and ample 

 directions have been already given in several works. 

 With the exception of a few woody species, fungi 

 when dried in the best possible manner, lose many 

 valuable characters that no amount of soaking in 

 water can restore ; therefore ample notes and sketches 

 made from living specimens are indispensable. 



For example, suppose a species of the genus 

 Agaricus, to which the edible mushroom belongs, 

 is collected, after having procured the spores as 

 follows, a hoH through which the stem will pass is 

 cut in a piece of paper, which is then passed up the 

 stem close to the gills, and fixed in this position by 

 passing a pin through the stem below the paper ; if 

 left in this way, the plant being supported in its 

 natural position for a few hours in a damp place, the 

 paper will be found marked with lines of spores 

 which have dropped from the gills. Then the form of 

 the pileus, which may be conical, depressed, &c, its 

 surface is sometimes covered with a sticky gluten, 

 with warts or scales, or of a silky or fibrous appear- 

 ance, the margin, or sometimes the whole, is striate. 

 The presence of fragments of the veil remaining 

 attached to the margin also requires notice ; the 

 shape of the stem, surface, texture, appearance of 

 ring if present ; next a section is required through 

 pileus and stem, this shows thickness of flesh of 

 pileus, also its consistence, changes of colour in the 

 flesh after being cut must be noted. The shape of 

 the gills is important, but more so the relation they 

 bear to the stem ; they are described as free when 

 not touching the stem (fig. 150), adnate when fixed to 

 the stem but not running down (fig. 149) ; decurrent 

 when grown to the' stem, and running down it for 

 some distance (fig. 151). In some species they are 

 much crowded, in others distant ; sometimes forked 

 or connected by veins, and the margin is sometimes 

 minutely toothed ; the colour also should be ascer- 

 tained at different ages. It has already been stated 

 thai the stem frequently differs from the rest of the 

 hymenophore, the pileus and trama, in structure, 

 being frequently more cartilaginous. This difference 

 is expressed by Mr. W. G. Smith in his excellent 

 "Analytical Key to the British Agaricini," as 

 follows : " Hymenophorum distinct from the fleshy 

 stem," — stem separated from pileus by a sharp 

 demarcation, as if the two were imperfectly arti- 

 culated, gills free. "Hymenophorum confluent and 

 homogeneous with the fleshy stem," — stem passing 

 insensibly into the pileus, and not furnished with a 

 cartilaginous bark, gills adnate or decurrent. " Hy- 

 menophorum confluent with, but heterogeneous from 

 the cartilaginous stem," — stem passing without inter- 

 ruption into the pileus, but differing from the latter 

 in being furnished with a cartilaginous bark ; gills 

 decurrent or adnate. 



Some agarics and also other fungi possess a charac- 

 teristic smell or taste. A coloured sketch will show 

 the size, colour, and if a section be also drawn, the 

 relation of parts ; care must be taken to obtain the 

 stem entire as the characters of the base — rooting end 

 — are of value. The genus Agaricus is broken up 

 into four primary divisions depending on the colour 

 of the spores, which may be white, pink, brown, or 

 black ; the white spores are best collected on black 

 paper, the others on white. In many leaf-parasites 

 the spores are stipitate, and when as is too usual, a 

 portion of a pustule is scraped off on the point of a 

 lancet, the pedicels are seen to be very short, owing 

 to having been cut through. A better plan is to make 

 a section through a pustule, when the arrangement of 

 the uninjured spores can be studied. To see the 

 mode cf attachment of the spores in moulds, they 

 must be examined as opaque objects under a low 

 power, and without a cover glass, as the application 

 of moisture or pressure causes the loosely attached 

 spores to fall away from their support, afterwards 

 the plant can be placed in water and examined 

 under a higher magnifying power, to ascertain the 

 nature of the hypha;, noting the presence or absence 

 of septa, the angular divergence of the branches, 

 also the shape, size, and colour of the spores. (See 

 figs. 152, etseq.) 



In the Ascomycetes a section is indsipensable. 

 After describing the external characters, a section 

 shows arrangement and form of asci and paraphyses 

 (fig. 164). It is usual to measure the spores in decimals 

 of an inch, or a millimetre ; the tubercles, warts, and 

 spines sometimes occurring on the cell wall require 

 notice. Habit, whether solitary, gregarious, or 

 crowded, also habitat, which differs widely in dif- 

 ferent species, must be noted. 



In microscopical examination it will be found 

 that the tissues and spores are frequently so hyaline 

 that without the aid of some colouring re-agent, the 

 structure cannot be satisfactorily made out. Chino- 

 line blue, known commercially as " Aniline blue, 

 No. 13," is useful and will stain living protoplasm, 

 as the amoeboid cells of the myxomycetes. In spores 

 there are frequently bright globular spots commonly 

 called nuclei, but which are in reality vacuoles. True 

 nuclei may be seen in an ascus previous to the forma- 

 tion of its sporidia. A solution of iodine is also 

 useful for staining tissues. 



What a lot of trouble, and all about fungus ! The 

 foregoing, or some similar feeling will undoubtedly 

 pass through the mind of many who may glance over 

 this contribution. 



If the trouble constitutes the pleasure, success is 

 certain ; not only in the study of fungi, but in every 

 attempt to solve a problem in nature. Before 

 classification can be understood or appreciated, a 

 sound knowledge of structure and relative value of 

 the various parts of a fungus must be thoroughly 

 grasped. 



