38 



FUNGI 



often edible, at least in the young state ; few are 

 positively poisonous. 



(1) Of tlie mostly subterranean and truffle-like 

 Hymenogastrei, one genus, Gautiera, affords an 

 interesting transition from the Hymenornycetes, 

 its hymenial depressions remaining open and un- 

 covered by any differentiated peridium. In the 

 remaining types ( Hymenogaster, &c. ) the gleba 

 contains many closed internal hymenial chambers, 

 but remains continuous with the simple per\dial 

 coat. 



(2) The Sclerodermei differ little from the pre- 

 ceding, save in the more differentiated peridium, 

 from which the gleba dries away in a brittle net- 

 work, lining the chambers, which become filled with 

 spores. Scleroderma vulgare is sometimes used as 

 an adulterant of truffles, but is commonly regarded 

 as inedible. 



(3) In the simplest Lycoperdinei or puff- balls 

 the gleba may remain unchambered, but the tissue 

 of the gleba usually breaks up into a woolly mass 

 of dried hyphse ; hence the peridium when l>roken 

 on ripening discloses a dusty mass of threads and 

 spores ( Lycoperdon, Bovista). See PUFF-BALL. 



(4) In another series, the Phalloidei in the 

 widest sense, we have a very singular series of forms. 

 This begins with the simple earth-star (Geaster), 

 which is essentially a puff-ball with outer and inner 

 peridium, of which the outer opens into radiating 

 lobes. In Batarrea, the gleba, covered with the 

 inner peridium, becomes raised upon a long stalk ; in 

 Phallus (see fig. 4, e,f, g ) the outer peridium, fibrous 

 outside, becomes gelatinous within, while the stalk 

 pushes the gleba through the inner peridium also, 

 as a naked cap from which the spores drop away ; 

 while in Clathrus it is the inner peridium which 

 expands as a large network. 



(5) In the last series, that of Nidulariei, the 

 external peridium opens, disclosing several separate 

 'peridioles,' each containing a hymenial tissue, 

 which breaks down into a mass of spores. These 

 are the ' bird's-nest fungi' (Cyathus, Nidularia, 

 &c. ). The origin of the Gasteromycete sporocarp 

 from its mycelium appears to be without any 

 sexual process, but by a process of direct growth and 

 ditterentiatkm of an upgrowth upon its mycelium. 

 In Hymenomycetes a sexual process has been some- 

 times described, but not with absolute certainty. 

 We know, however, how constantly the abundant 

 nutrition of an organism leads to the relapse from 

 sexual to asexual multiplication. 



As an appendix to this outline of classification, 

 it is necessary to note that we not unfrequeritly 

 find sterile mycelium forms, to which any definite 

 systematic position frequently cannot be given. 

 Such are, for instance, the well-known Racodium 

 cellare of wine-cellars. There has been much dis- 

 pute over the nature of the complex strands of 

 Rhizomorpha, now regarded as belonging for the 

 most part to Agaricus melleus, while the old genus 

 Sclerotium has long been recognised as a resting 

 state of many diverse forms e.g. Ergot. 



Germination. -Most spores are capable of im- 

 mediate germination : such are most acrospores 

 ((fonidia), almost all acrospores, and most spores of 

 Hymenomycetes. Some, however, require a period 

 of rest : such are most oospores, zygospores, winter 

 spores, &c. Although some spores perish almost 

 immediately, many others exhibit considerable 

 powers of resistance to heat, cold, drought, &c. ; 

 those of some moulds have been germinated from 

 herbarium specimens three to ten years old. For 

 germination we require a reasonable temperature, 

 varying with the species, with supply of oxygen 

 and moisture ; nutritive matter may also be neces- 

 sary. Many spores, however, have never as yet 

 been observed to germinate at all, notably those 

 of the truffle and some other Ascomycetes, of most 



Gasterornycetes, and of a few Hymenomycetes, 

 including even the common mushroom. 



Nutrition and Mode of Life. The characteristic 

 absence of chlorophyll renders the fungus unable 

 to decompose carbonic anhydride. Hence it must 

 depend upon organic compounds already formed. 

 Almost any soluble carbon compound, not too 

 poisonous or too fully oxidised (such as formic 

 or oxalic acid, urea, &c. ), will, however, serve for 

 this, and similarly with most nitrogen compounds, 

 even urea. The constituents of the ash can also be 

 obtained from a wide range of substances. Peni- 

 cilliurn grows best in a solution of proteid (peptone) 

 and sugar, yet can be grown, of course with 

 diminishing vigour, upon a whole series of poorer 

 solutions, down to ammonium acetate. All of 

 course give off' carbonic acid in respiration, and a 

 few are remarkably phosphorescent. 



Such facts help us more clearly to understand the 

 wide range of habitat presented not only by the 

 different members of the group, but by the same 

 species. Those fungi which normally obtain their 

 organic matter from the dead organic matter of 

 decaying bodies are termed saprophytes, while 

 those which obtain them from living plants or 

 animals are termed parasites. The former is doubt- 

 less to be regarded as the primary state of things, 

 and includes the great majority of fungi, yet many 

 normal saprophytes exhibit 'facultative parasit- 

 ism,' and conversely normal parasites may exhibit 

 'facultative saprophytism. ' Many saprophytes re- 

 quire a specific substratum e.g. dung, feathers, &c. 

 just as many parasites have only a single host ; 

 others again have a very wide range of habitat. 

 The chemical effects of the growth of fungi, with 

 which, for physiological purposes, we may also 

 reckon the Bacteria (q.v. ), upon organic substances 

 are outlined under FERMENTATION and PUTRE- 

 FACTION. The relation of specific parasites to 

 their hosts, besides mention in the various special 

 articles, such as ERGOT, MILDEW, and RUST, is 

 more generally treated under PLANTS (DISEASES OF) 

 and PARASITIC PLANTS ; the pathological bearings 

 (the GERM THEORY) at GERM, and articles there 

 cited. That remarkable adjustment of fungus and 

 host which rises beyond the pathological level into 

 the healthy and permanent mutual adaptation 

 known as Symbiosis (q.v.) is described, for the 

 association of fungus and alga, under LICHENS ; 

 that of fungus-mycelia with the roots of phanerog- 

 amous trees is the so-called Mycorhiza. 



Uses of Fungi. Of species used in medicine, the 

 only one now of importance is Ergot (q.v.): the 

 narcotic use of the Siberian fungus has also been 

 described under AMANITA. Amadou (q.v.) and 

 Moxa (q.v.) are old sources of tinder, and Poly- 

 porus squamosus, cut in slices, was much used for 

 razor-strops. But the chief use of fungi is for food, 

 and in the manufacture of Ketchup (q.v.). 



Although few fungi are used as food, and most 

 popularly regarded as poisonous, the positively 

 dangerous species are really by no means very 

 numerous. Yet the risks of incautious gathering 

 must not be understated, since not only are some 

 edible fungi liable to be confounded with poisonous 

 forms, but some normally wholesome forms acquire 

 poisonous properties under particular circumstances, 

 although whether this be due to definite variation 

 or to the chemical changes of incipient decomposition 

 remains doubtful. Hence our common mushroom 

 is excluded from the Italian markets. There is no 

 certain rule which can supersede the need of ex- 

 perience and caution in discriminating wholesome 

 from unwholesome forms, the popular beliefs e.g. 

 that the latter only will discolour a silver spoon if 

 stirred with it while being cooked, or that they are 

 more readily deliquescent being without founda- 

 tion. Nor does colour or odour afford any certain 



