———(e} =o) ———<) =f) —") —T =—=——(9 ————F] ——_—J ——_—_ ———— | (e) =>=_—r- ———J —— yy) INTRODUCTION [O.- THE STUDY OF FUNGI “M.C.COOKE __ yy. a" ‘ . - « - . - 7 dhe a . ‘ < . Pro “ = “9 . * « a . ¥ . “ ‘ = of 7 .- é D * ’ ite « ~~ Ps 7 - hd J , a Peg’. i A hae 5 \ ‘ _— . ‘ + a | 4 re a an 7% ' foal . . ee Leal a ‘ A F (as . x ¥ ' ‘ 3 r a“ ¢ 7 >, “ ‘ Ve - «% « : - read ? . a oa 4 OS = lex 7 ‘ si v « > ‘ 4 7 7 = a ee a ‘ vis 4 be aa ‘ : . a 7 ou + ; A ." 5 e 7 * 5 =, ; : ’ qt '. J'- - - = « 7 7 * a : i. oe i a oe on lee ® me - . + * + ins hy fan) 5 , Lb ee : F p en Coe ath. Qa » : = “ a aan) - .% — © « t io af - o> 4 . — A y ras - A ar Fs ‘ A = es *) * Be ‘ 7 * a) a ~~ 4 J ’ ‘ 4 ) i a s - wy aw / ie . = ' oe aN" oe K. ' a = : ‘ hss e hoch - 7 a ee bf > ; ~ +F = i ee ee ¥ A a + + A a2 ma! ‘Se Set a + i> eee Ae ees a) 3 ya Sepa ahe Har ey re 9 atinje aioe ta hee aa ite eal : Jit , UNIV, Fo29NTO, 24: . Y OF > ba LIBRARY OF PEPaAR TMs NT OF BOTARLY nin 92 7004 XY &, ~ 4, yy, v ‘ Digitized by the Internet Archive in 2010 with funding from University of Toronto http://www.archive.org/details/introductiontosOO0cook ~~ BIGE. DEPT, WHY, TORONTO. INTRODUCTION fae STUDY OF FUNGI THEIR ORGANOGRAPHY, CLASSIFICATION, AND DISTRIBUTION FOR THE USE OF COLLECTORS BY M. C. COOKE, M.A., LL.D., A.LS. LONDON ADAM AND CHARLES BLACK 1895 PREFACE THE Introduction to Cryptogamic Botany, published by Berkeley in 1857, was for a long time the only volume, in English, which could introduce the inquiring student to a systematic knowledge of Fungi. Later on, this work was discovered to be insufficient, inasmuch as it was more suited to the requirements of an advanced student than an inquirer ; so that the field was left open for a more popular and ele- mentary work, which, under the title of Fungi: their Nature, Influence, and Uses, appeared in 1875, subsequently passing through several editions. The rapid advance in knowledge of the life-history and development of these organisms during the past ten years, and especially the large scheme of classification earried out by Professor Saccardo, made it essential that, in order to keep pace with the times, a guide and introduction should be prepared and published for the use of students, which, whilst not superseding the volume of 1875 as a popular instructor, should treat the subject more after the manner of a text-book, adapted to the illustration of recent discoveries, and an explanation of the methods of classification. The following pages are the result of an effort to supply an acknow- ledged want, which I have executed under the impression that it is probably my last contribution of any importance to British Mycology. For many of the illustrations the publishers and myself duly acknowledge the kindness with which they have been placed at our disposal by the publishers of the works from vi INTRODUCTION TO THE STUDY OF FUNGI whence they are taken. A large number of the woodcuts will be recognised as formerly belonging to my Handbook of British Fungi, the use of which has now been granted by Messrs. Swan Sonnenschein and Co. We are also under obligations to the publishing committee of the Society for Promoting Christian Knowledge, to the proprietors of the Gardener's Chronicle, to Messrs. Kegan Paul, Trench, Trubner, and Co., Messrs. Macmillan and Co., and Messrs. Chatto and Windus; for which they will please accept our acknowledg- ments. Beyond this brief prelude I need not advance, as, under any circumstances, readers would prefer taking their evidence from the chapters which follow than from any professions or explanations in a preface. To the student who seeks for assistance I have offered all that I had to give, in the hope that it will be found sufficient for his need. M. C. COOKE. Lonpon, 1895. CONTENTS CHAPTER 4 PAGE INTRODUCTION : P : ; é : ; 1 PAR. I ORGANOGRAPHY CHAPTER Il THe MyYceELium . : 2 : ; : F 9 CHAPTER III THE CARPOPHORE 22 CHAPTER. LV Tae RECEPTACLE P ; f : s ; 31 CHAPTER Vi THe FRUCTIFICATION : : : A : : 41 CHAPTER VI FERTILISATION . ; ; , : : : 53 Vill INTRODUCTION TO THE STUDY OF FUNGI CHAPTER VII DICHOCARPISM CHAPTER VIII SAPROPHYTES AND PARASITES CHAPTER IX CONSTITUENTS PART i CLASSIFICATION CHAPTER X FouNGI IN GENERAL CHAPTER XI NAKED-SPORED FuUNGI—BASIDIOMYCETES CHAPTER XII HYMENOMYCETES . CHAPTER XIII Pourr-BaLtL FunGI—GaASTROMYCETES CHAPTER XIV AscIGERous FunGI—ASCOMYCETES CHAPTER XV Discoip FunGI—DIscoMyYcETES PAGE 64 73 95 119 126 149 164 CONTENTS CHAPTER XVI SUBTERRANEAN FuNGI—TUBERACEAE CHAPTER XVII CapsuLAR FuNGI—PYRENOMYCETES CHAPTER XVIII GAPING FuNGI—HYSTERIACEAE ’. CHAPTER XIX ConsuGaTING FuNGI—PHYCOMYCETES CHAPTER XX Rust FunGI—UREDINEAE CHAPTER XXI Smor Fune1—USTILAGINES CHAPTER XXII IMPERFECT CAPSULAR FUNGI—SPHAEROPSIDEAE . CHAPTER XXIII MovuLps—HyPHOMYCETES CHAPTER XXIV MicroBES—SCHIZOMYCETES AND SACCHAROMYCETES CHAPTER XXV Stime Founci—MyxomyceEtreEs 197 277 290 304 x INTRODUCTION TO THE STUDY OF FUNGI PART III DISTRIBUTION CHAPAHE <5 V1 PAGE CrNsusS OF Foner Y g ; . ; . 319 CHAPTER XXVII GEOGRAPHICAL DIsTRIBUTION E ; ? ; . ewe CHAPTER XXVIII APPENDIX ON COLLECTING ; : : ? . 0845 GLOSSARY ; : , : : P . ‘853 INDEX . : ; é P : . . 3858 CHAPTER I INTRODUCTION THE student will expect to find in an Introduction to the study of any subject some definition and delimitation of that subject —a task difficult in all cases to accomplish with brevity, and within the compass of a technical description, but one of in- creased difficulty when the subject is so extensive and com- plicated as Fungi. In past times definitions have been hazarded which appeared at the time to be incontestable and complete, but within a short period they became insufficient. That they are plants of a low organisation must be conceded, and also that they belong to the lowest section, or the Cryptogamia, in which the reproductive organs are more or less concealed ; but the old characteristics of Algae as cellular plants subsisting in water ; of Lichers as subsisting in air, and not upon the matrix on which they flourish ; and, finally, of Fungi, which derived their sustenance from the matrix, have had to be discarded as in- sufficient. It is now known that aquatic Fungi are not an impossibility, that Algae may grow in a damp atmosphere, and that some portion of the substance of Lichens may be derived from their matrix. Seeing the difficulty of obtaining positive characters, negative ones have been tried; but these again have failed to give satisfaction. In one of the most recent works which has attempted to deal with this difficulty we meet with the following as one of the “leading characters.” It is to the effect that “Chlorophyll, the green colouring matter so general in the vegetable kingdom, is entirely absent from fungi.”? Admitting this to be true, may it not be maintained that there 1 Massee, British Fungi (1891), p. 1. i 2 INTRODUCTION TO THE STUDY OF FUNGI are probably some lichens or some algae in which true chloro- phyll is not present ? But speaking of them as a whole, we are justified in saying of Fungi that they are “cryptogams without chlorophyll,” and in this we shall embody the most important characters of the group ”—a general definition which may be accepted without reservation. Except for one or two small families, we could add also “ without determinate sexuality.” Previous to this, Berkeley had pointed out that the definition was imperfect which described Fungi as “ deriving nourishment by means of a mycelium from the matrix, and never producing from their component threads green bodies resembling chlorophyll,” * for, he goes on to observe, “it is true that a few Algae, such as Botrydium, do probably imbibe some- thing from the soil by means of their rootlets, which can scarcely be mere holdfasts”; and again, “ When we examine Fungi more closely, we shall have reason to believe that there are exceptions here also as to their deriving nutriment from their matrix. I have, for instance, found a Cyphella on the hardest gravel stones, where the fine mycelioid threads, by which it was attached, could not possibly derive any nutriment except from matters conveyed to it by the air or falling moisture.” To the latter portion of the paragraph, giving the negative character of the absence of chlorophyll, Berkeley, however, gives his adhesion. A logical definition, therefore, so commonly fails, that we shall excuse ourselves from attempting a new one, simply indicating a few points to be borne in mind whilst perusing the following pages, from whence alone a general idea can be obtained of such a polymorphous group. Lindley divided all the Cryptogamic plants into two sections, the Acrogens, growing at the summit, including the Ferns, Mosses, and their allies, and the Thallogens, which embraced Algae, Fungi, and Lichens. Hence we conclude that Fungi are not only Cryptogams, but of that section in which there is no true root or distinct stem with foliaceous appendages. Although the Rev. M. J. Berkeley was, in the main, responsible for Lindley’s classification of the Cryptogams, it is out of date and inapplicable in the present 1 Introduction to Cryptogamic Botany, p. 235. INTRODUCTION 3 day, when other and improved methods have been brought into use. Instead of the term Zhallogens for the cellular Crypto- gamia, it would be preferable to call them Thallophytes, and, for the rest, Bryophytes would include Mosses and their allies, whilst Pteridophytes would be represented by the Ferns. Thallophytes, in a general sense, which will be sufficient for practical purposes, consist of those plants which grow in water, and obtain their sustenance therefrom, commonly known as Algae ; and those which flourish in the air, being sustained by the decomposition of the matrix on which they flourish, as Fungi; or drawing their sustenance from the air, and rarely, or but slightly, from the matrix, as in Lichens. Here again a negative feature may be interposed with advantage, to the effect that Lichens are not of a fleshy or putrescent, but of a dry and leathery consistence, whereas in the bulk of Fungi the substance is, either entirely or in the early stage, soft and fleshy, becoming indurated or putrescent with age. The distinctions between Algae and Fungi will never cause any practical difficulty, because the Saprolegnieae, which are aquatic, and approach Algae most nearly in habit, derive their sustenance from the matrix on which they are parasitic by means of penetrating mycelial threads, whereas Algae are simply attached by root-like or sucker-like extensions to the matrix, from which nothing is absorbed. The relations between Fungi and Lichens are much more intimate, and in extreme cases approach each other so closely as to be distinguished with difficulty even by experts. Whole genera are still claimed by mycologists on the one hand, and by lichenologists on the other. Still it must be remembered that these are extreme cases, and that amongst the larger Fungi, especially in the great group of Hymenomycetal Fungi, there is but little suggestion of Lichen affinity except in such genera as Cora, Dictyonema, Pavonia, etc. Another exceptional case may be found in the Nostoes, which are Algae, simulating or so closely resembling TZvemella, a genus of Fungi, that microscopical examination may be necessary for their discrimination. Habitat may in some cases serve to indicate the character of the Thallophyte. For instance, all the parasites on living leaves which are not of insect origin are Fungi, such as the 4 INTRODUCTION TO THE STUDY OF FUNGI smuts and rusts which are so destructive to crops. There are often to be seen discoloured spots upon living leaves which cannot be attributed either to insects or Fungi. It is a common mistake with novices to infer that all leaf spots are necessarily caused by parasitic Fungi. Again, all the fixed or vegetable parasites on insects are Fungi, whether moulds or the larger club-shaped species of Cordyceps. Another caution becomes necessary lest the pollinidia of Orchids, which are sometimes seen temporarily attached to living insects, should be con- founded with true parasites. Putrescent vegetable, and some- times animal substances, give rise to Fungi, but dead wood and the bark of trees may also support Lichens as well as the living bark, on which Fungi are rarely found, except in cases of incipient decay. No difficulty need be anticipated in respect to Thallophytes found growing upon the ground, inasmuch as the Lichens which have a terrestrial habit would scarcely be con- founded with Fungi at any time, but especially after the perusal of succeeding chapters on the details of structure in the several orders. It should be understood that the above- named distinctions are not so much of scientific value as they may be useful as guides to collectors. The mycelium of Fungi is so general, although at times nearly obsolete, that it must be regarded as somewhat analogous to the thallus of Lichens, but not to be confounded therewith. In the Agarics this mycelium is commonly termed the “spawn,” and consists of delicate threads, which traverse the soil or the rotten wood upon which the Fungus is grown. In some instances a strong mycelium is developed, but no perfect Fungus is produced upon it. An instance may be found in the substance called XYylostroma giganteum, which forms thick sheets like leather, destructive of wood of solid texture. It is doubt- less a degraded form of wood-destroying Hymenomycete The moulds and the mucors produce at first decumbent barren threads, which constitute the mycelium out of which sub- sequently the fertile threads arise. In the “rusts” or Uredines the cushion-like base of the pustules is surrounded by the delicate threads of mycelium. Going back to its origin, we discover that the initial spore, or spores, upon germination pro- 1 See next chapter, p. 10. INTRODUCTION 5 duces a delicate thread which, either directly or indirectly, origin- ates the mycelium upon which the Fungus of the new generation is developed. In the Agarics it is held that a large number of spores germinate, and produce the mycelium from which a single individual or a cluster of young Agarics are evolved. In some instances the mycelium is undoubtedly perennial, and produces a crop of Agarics in successive years, but much remains still to be known of the life-history of the Agarics in the interval between the maturity of the spore and the first evidence of the genesis of a new plant.’ In some of the smut Fungi the germinating spore produces a thread which develops secondary spores, and these in their turn produce tertiary spores before the true mycelium-forming spores are developed. In the Uredinesthe earliest spore-forms, called “pro-mycelial spores,” are produced from the germinating threads of the latest spore-forms or teleutospores, which in turn give rise to the mycelial threads ? that enter and form a new mycelium within the tissues of the invaded host-plant. In the Zrysiphei the mycelium forms an external coating on the surface of the living leaves, producing at first conidia, and ultimately the perithecia or spore-capsules of the perfect Fungus. Indeed, as a rule, the mycelium repre- sents the vegetative system of the Fungus upon which, under varied forms, the reproductive organs. with their appendages are produced. The universality of this mycelium in Fungi was formerly held to be as certain an indication of distinction between a Fungus and a Lichen as the production of a thallus was then held to be a sufficient distinction between a Lichen and a Fungus. In later times it has come to be understood that the hyphal elements in Lichens and Fungi are virtually the same. 1 In this connection may be consulted Brefeld’s researches into the life-history of Coprinus stereorartus. 2 See post, chap. xx. BIBLIOGRAPHY BERKELEY, M. J. Outlines of British Fungology—Introductory Matter. 8vo. Plates. London, 1860. — Introduction to Cryptogamic Botany. Roy. 8vo. Cuts. London, 1857. — Articles on ‘‘ Vegetable Pathology,” in Gardener's Chronicle, from 1855. Linviey, J. Vegetable Kingdom. 8vo. Cuts. London. 2nd Edition. 1847. Cooxr, M. C. Fungi: their Nature, Influence, and Uses. Sm. 8vo. Cuts. London, 1875. — _ A plain and easy Account of British Fungi. Sm. 8vo. Plates. London. — Romance of Low Life amongst Plants. 8vo. Cuts. London, 1893. Boupier, E. ‘‘Considérations sur ]’Etude microscopique des Champignons.” Bulletin de la Société Mycologique de France, vol. i., 1885, p. 134. De Bary, A. Comparative Morphology and Biology of the Fungi, Mycetozoa, and Bacteria, English Translation. Roy. 8vo, Cuts. Oxford, 1887. TAVEL, F. von. Vergleichende Morphologie der Pilz. Jena, 1892. PART I ORGANOGRAPHY CHAPTER II MYCELIUM In such an immense group as the present, including almost an infinite variety of form, it is extremely difficult to generalise, even the morphology, beyond that of the mycelium, which re- presents the vegetative system, the carpophore, which supports the fructification, and, finally, the fructification itself, with the organs associated therewith. This, in fact, reduces the whole scheme of structure to its lowest terms, that of the vegetative system and the reproductive, since the carpophore is but a development of the vegetative, and a link between that and the fructification which it is intended ultimately to bear. The details of the varied modifications, which are to accomplish the two purposes of growth and rejuvenescence, can only be de- scribed under the great primary divisions of Fungi, where both vegetation and reproduction conform to some definite type. As a whole, the organisms which are associated to- gether under the common denomination of Fungi are the most protean and polymorphic in the entire vegetable kingdom, | and present great difficulties in the way of generalisation. If we gather a mushroom from a mushroom bed, as usually cultivated, we shall discover, if we remove it carefully, that the stem, which represents in this instance the carpophore, or fruit-bearer, is attached to the soil by a mass of delicate white hyphae, or threads, which are the mycelium, or spawn. And if we remove the soil anywhere, we shall find that it is per- meated in all directions with these white threads. The artificial “bricks,” or spawn, which were employed in the construction of the bed, consisted of this mycelium in a quiescent condition, and by supplying sufficient moisture and 10 INTRODUCTION TO THE STUDY OF FUNGI heat, with a suitable matrix, the filaments of this mycelium have been revivified, and by a profuse and rapid growth they have spread over, and penetrated the whole of the soil of which the mushroom bed is composed, and constitute the vegetative system of the mushrooms which afterwards appear on the surface. This mycelium represents an important element in the morphology of all Fungi. It is rarely reduced to such small proportions as not to be recognised, but, practically, it is possibly never wholly absent. We may start, therefore, with what we may regard as an essential attribute of Fungi, and the representative of the purely vegetative system. Where- ever we see a Fungus of the mushroom type, whether we please to call it a mushroom or a toadstool, we may find the mycelium in the soil from which it springs. In the autumn, if we stir up and turn over any clump of dead leaves or other decaying vegetable matter in a damp situation, we shall be sure to find a profusion of this mycelium, even though no perfect Fungus makes its appearance, and it is at work on every dead stump and every fragment of rotten wood. Mycelium consists of hyphae or threads, usually septate, sometimes simple, but mostly branched, increasing by growth at the extremities, and gregarious, so as to form reticulated interwoven masses, either in a thin network or a densely-felted mass. In a certain sense they are analogous to the roots of flowering plants, and, like them, draw moisture and inorganic constituents from the soil or other matrix on which they may be developed. It is another axiom with Fungi that, by means of the mycelium, they derive their sustenance from the matrix on which they grow. It cannot be doubted that the growing points of the mycelium possess the power of penetration by the production of a ferment, since they are capable of pene- trating the hardest wood, disintegrating the cells, and reducing it to powder. The ordinary mycelium found amongst dead leaves has a power of disintegration, and soon reduces them, as well as twigs and stems, to a condition of humus; but the progress of mycelium in a dead trunk is quite as definite and certain. Who can doubt the disintegrating power of the mycelium of the “dry rot,” and it must be borne in mind that it is the mycelium in this instance which works the MYCELIUM II mischief. The hyphae forming this vegetative system may be immersed, and probably are so in the majority of instances, but they may also form a stratum on the surface, and adhere by haustoria or suckers, which are short branches designated for the purpose, or for that combined with the absorption of nutriment. The hyphae when young have colourless cell walls, but as they grow older the walls thicken and acquire colour, sometimes with an appearance of stratification. In some cases cross branches anastomose, or form clamp connections (Fig. 1). Gardeners are well aware that immense masses of white myceliumare some- times met with in turning over the soil. These mark the site of an old tree when part of the stump or.dead roots have been left to rot in the ground. Numerous instances are on record in which trees or shrubs, when planted in soil overrun in this manner with mycelium, have been killed, and when taken up the roots found ,, 1 _ Chain to be enveloped in mycelium. Practical men connections. are quite aware that this has occurred over“! De Bary: and over again, and yet some theorists contend that it is not possible, because the mycelium is a saprophyte, that is to say, flourishes upon dead organic matter, and not upon living tissues. Observation has nevertheless decided that in some instances a saprophyte may become parasitical, and a parasite may acquire the habits of a saprophyte. The instances may not be common, but are not impossible. Against theory we are prepared to contend, from experience, that we have seen plants killed, after planting in a soil overrun with mycelium, from no other assignable cause, and afterwards dug up with the roots enveloped in mycelium. It has been stated above that mycelium is usually colour- less, and it is generally so with the Basidiomycetes, but there may be exceptions, as in Corticiwm sanguineum, with its mycelium of a blood red, in Elaphomyces Leveillei, of a yellowish green, in Chlorosplenium aeruginosum, of a verdigris green, and in many of the Dematiaci, of a dark brown, or almost black. And so also it may differ considerably in quantity, from a few scattered threads to a dense matted felt. Even in this country 12 INTRODUCTION TO THE STUDY OF FUNGI it sometimes forms thick laminae many inches broad in old trunks, but in warmer countries it develops into a spongy mass, called Yylostroma in past times. These masses will fill up holes in a log nearly as thick as the wrist, and a foot or two in length, or they will spread in layers of an inch in thickness, a foot in breadth, and several feet long. The whole mass is made up of interwoven threads, almost as dense as cork when felted together, but wholly barren, so that it is uncertain whether they are the mycelium of a Polyporus or an Agaric. Having been furnished with a redundant supply of nutriment, they never advance beyond the vegetative stage. In the case of entomogenous Fungi, the mycelium will replace the whole of the tissues, even to the legs and feet, so as to form a com- plete cast of the insect, of which only the dermal covering remains unchanged. In such genera as Cordyceps and Empusa the filamentous structure is only seen in the earliest stage ; this soon gives way to a compact granular mass. The mycelium of the Mucedines, or moulds, when abundantly supplied with . moisture, develop rapidly and vigorously, but do not proceed with the fructification whilst the nutriment supplied is abnor- mally great. The conidial stage of the Hrysiphei will furnish examples of a thin superficial mycelium adhering by haustoria. In these cases a thin white web runs over the surface of living leaves, as in the vine mildew, and a mildew on the leaves of the maple, but it does not penetrate deeply into the tissues of its host, which it injures by choking up the stomata. Another superficial mycelium is that of Fumago, which forms black patches on the leaves of the lime and other trees, being especi- ally vigorous on those subject to honey-dew. In the sphaeria- like or capsular Fungi, the mycelium is confined, usually, to a few delicate threads at the base of the perithecia, but there are exceptions to this in some superficial species, where a subiculum or conidia-bearing mycelium is. present. Another form assumed by mycelia is that condition which has long been known under the name of Rhizomorpha, when it was suspected to be an independent Fungus, although no form of fruit had been discovered. It is now admitted that the several species are only the vegetative condition of other Fungi. One kind may be seen running between the bark and wood of MYCELIUM 13 dead trunks in long brown or black cords, as thick as whip- cord, flexible, but firm, and either branched or joined by cross connectives of the same substance, into a coarse net- work. These long cords may be many feet in length, and whitish internally, with a dark-coloured outer coat or skin. The tips of the growing branches are paler. This peculiar growth is very common in mines and other dark places, and glows sometimes with a phosphorescent light. Tulasne examined some specimens with a view to the discovery of the cause of their luminosity, of which Humboldt, amongst others, had given such an elaborate account. He found that all the young branches brightened with a uniform phosphoric light the whole of their length, and also the surface of some of the older branches. The latter when split open were dull, but after exposure for a time to the air they also became luminous. By keeping them moist, they preserved their phos- phorescence for several days. He also states that branches which had been dried for more than a month, when plunged into water, revived, and began to vegetate afresh, in a few days, by sending forth numerous branches, but they were only luminous on the surface of the new parts. One of our commonest Agarics, to be found on nearly every rotten stump, Agaricus melleus, is credited with being the complete develop- ment of one of the species of Rhizomorpha, which may be stated in this way—the cord-like Rhizomorpha is simply the persistent mycelium of Agaricus melleus, which grows on rotten stumps. We have no doubt that another form or variety of Khizomorpha is the mycelium, or vegetative con- dition of Polyporus squamosus, and others, with more or less certainty, are referred to other species of Agaric and Polyporus. Something of the nature of Rhizomorpha is found amongst dead leaves, mostly in long, simple, rigid black threads, which in size and appearance are not unlike horse hair. These are believed to be the mycelium—or rather, we should say, the permanent mycelium, to distinguish it from the filamentous white mycelium—of some species of Marasmius. In tropical and sub-tropical regions these horse-hair filaments are very common amongst dead leaves, and are known to be sterile conditions of several species of Marasmius. 14 INTRODUCTION TO THE STUDY OF FUNGI There is another condition which the mycelium of some Fungi assume that is something of a resting stage, and in former days these were classed under a genus called Sclerotiwm. They are in the form of hard, compact, irregular nodules, from the size of a pin’s head to that of a child’s head, according to the species. They are mostly dark coloured externally, and nearly white and horny within, with a firm cellular substance. We will commence with one that is well known, under the name of Ergot, and occurs on the spikes of rye, wheat, and many grasses, converting the ovary into a Sclerotiwm, or replacing the ovary with a Fungus growth, whichever view pleases best. These abnormal growths are three times as long as the ordinary seed of the rye or grass, elongated, and a little curved, so that they look like a horn ys. or spur projecting from the Pia. 2-—Hrgpt Borerone cenoeens ‘ear of pram, (lig ise of the substance is placed under the microscope, it will be seen to consist of a densely compact mass of cells, somewhat irregular from mutual pressure, with thick walls and rather oily contents. At last they are liable to become dissociated from the spike, and fall to the ground, where they will lie quiescent and unchanged through the winter. When spring arrives, active vitality recommences, and the sclero- tium germinates by producing one, two, or more—generally several —little slender twisted stems, with a globose head, reminding one of a pin. The stem is whitish, and the head of a pale purple. It is within the globose head that the fructification is produced. This latter is the mature Fungus of the Ergot sclerotium, and is then called Claviceps purpurea, one of the Sphaeriacei (Fig. 2). By way of illustration, we have indicated briefly the history and development of the Ergot sclerotium, but it will scarcely be consistent with the design of this chapter to repeat the process for other species. Another example may be found inhabiting the dead haulms of potato. First of all the haulms MYCELIUM 15 are covered with a dense felted mass of white mycelium. When this is fully developed, scores and hundreds of little black points appear in the midst of the hyphae, averaging in size from a grain of sand to that of a small bean. These become indurated and hard, and, in fact, properly-constituted sclerotia, internally composed of polygonal cells. These also subside into a con- dition of rest, in which they spend the winter, and germinate in spring. The re- sulting Fungus in this instance consists of similar slender twist- ed stems, but the head, instead of being globose,is cup-shaped, then flattened, bear- ing the name of Sclerotinia Inbertiana, or,as known in former ears, a species of > ; fth +. Fic. 3.—Sclerotia germinating and producing Pezizae Penizu, one of the Dis Ato D. Ascus and sporidia, E. Gard. Chron. AS.W.ock. comycetes (Fig. 3). Several other instances might be quoted in which the Sclerotiwm, when germinating, produced a species of Peziza, especially a large one common in company with the roots of the Wood Anemone. A large species of Russula, common in the woods, turns quite black when dead and decaying. On the gills of these decaying Russulae many sclerotiae will be seen, resembling in form small grains of barley. These germinate speedily, and produce a little Agaric (Collybia tuberosa). In Australia a sclerotium nearly as large as the fist develops a tough gill-bearing Fungus, shaped like a wine-glass, named Lentinus cyathus. But a still larger sclerotium, which has been known for years as “ Native Bread,” and grows as large as a child’s head, has been recently found to develop a white Polyporus with a central stem, and has been named Polyporus Mylittae.' 1 Grevillea, Dec. 1892, p. 37. 16 INTRODUCTION TO THE STUDY OF FUNGI We have briefly directed attention to the ordinary develop- ments of mycelium, whether filamentous or sclerotioid, but there are still one or two special modifications which must obtain a passing reference. Of these the mycelium of the Uredineae is deserving of mention, being formed within the tissues of living plants, and often starting centrifugally from a definite point of infection. The hyphae resemble ordinary mycelial filaments, but, like all internal mycelia, are delicate, branching and anastomosing so.as to form compact cushions or spore beds, or, in other cases, much diffused and scattered. In annuals or upon deciduous parts the mycelium is, of course, only annual, but if it passes into perennial parts, as it may readily do in shrubs and other perennials, the mycelium becomes perennial. Take, for instance, the Juniper, in which the Gymnosporangium may be sought for and expected regularly year after year. In such species as have a scattered mycelium there is not much difference between the mycelium of these and that of other endophytes, but when the mycelium is circumscribed, the tissues are hypertrophied, and starch seems to be accumulated in the deranged cells. Leaves thus attacked never repair the injury, and the diseased spots are the first to die, and occasionally drop out, as we have seen with the large clusters of perfect-spored pustules in Puccinia deanthi. The mycelium of the Peronosporeae is more diffused than that of the Uredines, commonly penetrating the whole plant, descend- ing into the stem and roots, and in the stems producing oospores, as the result of a sexual conjugation. In the Ustilagineae the mycelium is much more diffused than is usual in the Uredines, permeating the entire plant, and in perennial hosts producing fruit regularly year after year. The Phycomycetes, which include those mould-like Fungi which bear inflated sacs at the apices of their fertile branches containing numerous spores (J/ucors), have a mycelium without septae. The Mucors themselves are mostly saprophytes, and some of them have a profuse mycelium. The reproduction ‘is both asexual and sexual, the sexual being developed from the mycelium ; hence the mycelium in these Fungi, although at first only vegetative, becomes finally reproductive, and thus assumes a higher function. The process is after this kind: two short MYCELIUM 17 branches of the mycelium approach each other until they touch at their apices. The branches swell and become club-shaped, including a rich store of protoplasm. At length the upper portion of each club is cut off by a transverse septum, and the two apical segments are fused into a globose body, the walls at the point of contact being dissolved. Thus we have two thick supporters, with a globose body suspended between them, which is to become the zygospore, resulting from the conjugation and coalition of the club-shaped branches (Fig. 4). The succeeding steps need not be detailed; the zygospore acquires a thick outer coat, and then becomes a resting spore, which only germinates after a period of rest. The same mycelium therefore produces Fig. 4.—Zygospore of Mucor in course of formation. After De Bary. erect carpophores, or conidiophores, surmounted by an inflated vesicle containing conidia, an asexual generation, and also pairs of nearly sessile branches, which collide and form a zygospore between them, a sexual generation. Similarly, in other families the two kinds of reproduction are developed, asexual and sexual, from different parts of the same mycelium, but not precisely in the same way, yet the details do not affect the mycelium greatly, except in the family to be presently alluded to. The Lntomophthoraceae ' are those Fungi which are parasitic and destructive to insects, including the ordinary fly mould, 1 The Entomophthoreae of the United States, by Roland Thaxter, 1888, Boston, U.S. 2 18 INTRODUCTION TO THE STUDY OF FUNGI Empusa muscae. When the spore of one of these moulds alights upon the body of its favourite host-insect it sends out a germ tube, which enters the body at any favourable spot, and when this is once accomplished, it develops rapidly, at the expense of the tissues it replaces. It does not forma branched mycelium, but grows by the production of hyphal bodies (Fig. 5), which are short, thick bodies of variable size and shape, and these continue to multiply, by budding or gem- mation, until they fill the insect. It is Fic. 5.—Hyphal bodies possible that in some cases a mycelium in Entomophthoraceae. 3 : on ee of the ordinary kind may be produced. When the whole interior is absorbed, and of course the insect is dead, the vegetative stage ends, and the reproductive begins, by the protrusion into the atmosphere of conidiophores terminated by conidia, either singly or in bundles, until the body is covered with the conidia, ready to be dispersed. This is the asexual reproduction of conidia, but resting spores are also formed, which may be sexual or asexual, according to the species. In some cases the conjugation of two threads of the , mycelium, and in others the conjugation © of two of the hyphal bodies (Fig. 6), results in the formation of a zygospore. There is a peculiarity about the conidia which may be noticed, which is, that should a ripe conidium not be able to find or enter a host-insect, it can proceed to germinate and form a secondary conidium, which has the same power of infection, and may be more fortunate. If this also fails, the secondary conidium may pro- Fic. 6.—Hyphal bodies in duce a third, so that the vigour of the 2™omephthoraceae con- SS ath ‘ jugating. ‘ After Thaxter. conidia is kept preserved until able to infect a host. Possibly the Jsaria moulds, in the interior of insects, extend their mycelium in a similar manner by budding, as they are also granular rather than filamentous. In opposition to the views of some mycologists of ex- perience and repute, we still remain persistent in our adhesion MYCELIUM 19 to the vegetable nature of the Myxomycetes, and consequently regard the vegetative condition as upon an equality in function, if not in structure, with the mycelium. This was clearly the view of M. Léveillé, who termed it “a malacoid or pulpous mycelium.” We see no objection to its being called a plas- modium—the name does not alter its character or functions. De Bary was content to admit that the wall of plasmodia, as well as the cell-walls of spores and other parts, gave a distinct cellulose reaction, and possibly cellulose in some form is general in Myxomycetes. And further, according to the same eminent authority, the presence of cellulose is the only character show- ing that these organisms are in touch with the vegetable kingdom. This question we are not anxious to discuss further here. Swarm-cells with the power of movement are produced on germination from the spores of Myxomycetes ; these swarm- cells ultimately coalesce and form a plasmodium, which is capable of passing into a resting stage, and sometimes to become sur- rounded by a colourless membrane. There are no threads or filaments, as in a filamentous mycelium, neither in the sclerotioid mycelium is there a similar resemblance; in fact, there is no greater difference between a plasmodium and a sclerotioid my- celium than there is between a sclerotioid and a filamentous my- celium. From the plasmodium are differentiated the carpophores, the receptacles, and the fructification of a Fungus, even although the plasmodium or analogue of mycelium is not filamentous, but rather resembles a sclerotium in a soft and pulpy condition. Theoretically, mycelium originates with the germ-tubes which are protruded by spores or conidia upon their germina- tion. It is easy enough to observe the process thus far, produced artificially by placing the spores in a nutritive fluid, but in the case of the larger Fungi the operation cannot be carried much further under ordinary circumstances. In the case of Agarics it is concluded that the mycelium produced by a number of spores unite in the production of a single Agaric, so that one specimen is the produce of several germinating spores. We know that the soil contains a great mass of mycelium in places where Fungi are found growing. Worth- ington Smith says’ that the Agarics of the autumn spring up 1 Reproduction in Coprinus, Grevillea, iv. (1876), p. 53. 20 INTRODUCTION TO THE STUDY OF FUNGI from the mycelium formed during the fall of the previous year, and this mycelium has rested in the ground for twelve months. In digging up old pasture ground, or the dead leaves of an autumn which has passed, mycelium in a resting state is invariably found. We can hardly conceive of the preservation of the spores of an Agaric through the winter and an entire year, until the succeeding autumn, in any other way than by the production of a hibernating mycelium. The spores them- selves have too delicate an epispore to resist the effects of cold, and we know from analogy that the resting spores of Algae and Fungi, when known to be such, are provided with a special thick outer envelope. The spores of Agarics are not thick coated, and are incapable of hibernation; hence we are driven to the alternative of a perennial mycelium. A theory was once propounded that a conjugation takes place in the threads of mycelium which results in the production of a fertile Agaric, the whole of whose fructification is thereafter rendered fertile, but this view has never been accepted. Notwithstanding all the theories, we are still in search of the process of fecundation in Hymenomycetal Fungi. All that we can contend for is the persistency of the mycelium as the means whereby the Mush- room Fungi are carried through the winter and reproduced in the succeeding year. There is a prevalent opinion, in Germany at least, that “root fungi” are not always injurious to trees, but sometimes, on the contrary, beneficial. Frank? states that certain trees are unable to derive nutriment direct from the soil, but do this by means of a mass of Fungus hyphae which entirely invests the root, to which he gives the name of Mycorhiza. It makes its appearance first on young seedlings, and is replaced by fresh formations on older roots. He found it on the roots of every tree examined belonging to the Cupuliferae, and occasionally on willows and conifers, but considers it may only be formed in soils which contain a large amount of humus, or undecomposed vegetable remains. Through the Mycorhiza the tree absorbs not only water and mineral con- stituents, but organic substances derived from the humus. Two or three other authors have since confirmed this in 1 Journ. Roy. Micr. Soc., vol. v. (1885), p. 844; vol. vi. (1886), pp. 113, 663. pp MYCELIUM 21 the most important particulars, but not as to its constant presence. The mycelium is the active agent by which Fungi disin- tegrate decaying organic matter, or prey upon and destroy the living, and so far as they derive nourishment from the sub- stratum, their nutrition resembles that of flowering plants, but beyond this the mycelium is active in decomposing the organic matrix, the product of which is not required or taken up by the Fungus. Hence there are forms which are satisfied with taking up from living or dead substrata only so much as is needed for the construction of their bodies, as well as those which in addition produce copious decompositions in the substratum and destroy it. We may assume that the mycelium exerts a ferment action upon the matrix, although the quantity of the ferment may be small, and that these ferment actions first take place in order to convert a portion of the substratum into a form which is capable of nourishing the Fungus. In the headings of the several chapters we have used terms in their general sense, representing the myceliwm as equivalent to the vegetative system, the carpophore as the supporter of the fructification, or intermediary between the vegetative and reproductive systems, whilst receptacle is employed in a sense different from that which it holds in other branches of botanical science, and should be accepted literally as representing the envelope of the fructification, whatever its form may be, when any envelope is present. This definition is necessary so as to prevent confusion of the terms we have employed in a general sense, with their special application elsewhere. CHAPTER III THE CARPOPHORE ! THE mycelium, in all its forms and variations, is but the prelude and preparation for the development of such parts or organs as may be necessary for the subsequent processes of reproduction. The production of the carpophore is, in itself, only a continuation of the process of vegetation, but that vegetation is no longer subterranean, subcuticular, or creeping ; invariably it is more or less, in development, at right angles to the mycelium, and may be accomplished by the production of special erect branches, or a stem compounded of an indefinite number of erect threads, agglutinated and consolidated together ; whether it is to be the conidiophore of a mould, the stroma of a Cordyceps, the club of a Geoglossum, or the stalk of an Agaric or Boletus, it is the fruit-bearer, or carpophore, which is destined to bear the fructification of Fic.7.—Unbranched the species. It may be reduced to its lowest carpophore >| terms, and be practically obsolete, so that the Lopalomyces. 3 4 P receptacle is sessile, or nearly sessile, upon the mycelium; still there is normally and technically a carpophore, which supports the organs of reproduction. In the larger moulds generally the ascending hyphae are branches of the mycelium, and do not alter much in character except in being rather thicker and with more rigid walls, so as to maintain an erect position. These erect threads are in most cases clustered together, and are modified in ramification 1 The term ‘‘carpophore,” in its special sense, is usually restricted to forms of a distinct fruit, consisting of an aggregate of reproductive organs. THE CARPOPHORE 23 according to the different genera. In certain cases, as in Aspergillus and Rhopalomyces, they are simple and unbranched up to the top (Fig. 7), but in the larger number of genera they are branched in the upper portion. Very often a great number of these car- pophoresare produced in a large woolly- looking patch, not rarely for an inch or two in length. Endo- genous moulds, which produce mycelium in the interior of the tissues, send up little tufts of carpophores through the stomata, and these grow in patches. Well-known examples are to be found in the genus Fru. 8.—Branched carpophore of Peronospora. Peronospora, such as the mould on parsnips and onions (Fig. 8). In the genus Ramularia the mycelium is internal, and the conidiophores pass in the same manner out into the atmosphere; but they are usually short, often unbranched, with a single conidium. In Oidium the mycelium is external, and the erect hyphae are simple, but it is only the short lower portion which is truly a carpophore, for the upper portion is constricted successively, and the joints fall off as they are formed, and become conidia. There are also genera in which the carpophore is compound —that is to say, a number of threads are combined so as to -form a common stem, which is consequently thicker and more permanent. Either these individual hyphae diverge at the apex, or they remain united and form a capitulum, as in Stedbwm. When the combined threads form only a short erumpent stroma, as in Zwbercularia (Fig. 9), the carpophore is reduced nearly to its lowest denomination, and is scarcely more than an erumpent pustule. All the foregoing forms are repeated in 24 INTRODUCTION TO THE STUDY OF FUNGI the Dematioei, or black moulds, the chief difference being in the dark-coloured, more rigid, and carbonised hyphae. Resembling the moulds in external habit, the Jucors resemble them also in the carpophore, which is sometimes forked two or three times, but not dendritically branched. In Pilobolus the carpophore is curiously inflated, like a bladder (Fig. 10). We have in remembrance a pseudo-analogy which some few years since became current—that the type of organisation in a Muce- dinous mould was repeated, with modifications, in the structure of Agarics. The mycelium, it was con- tended, was common to both. From - the mycelium arose the carpophore, Fic. 9.—Compound carpophore which was a compound stalk, in of Tubercularia. A 7 which a myriad of erect hyphae were combined; in the pileus the combination was continued of the branches, and then down to the _ basidia, which were the terminals of the branchlets, with the spores, or conidia on spicules, as in such a genus as Lhinotrichum. This was a fanciful representation, since the analogy, even if it held good elsewhere, was broken at the hymenium, and the basidia were therefore not in continuity with the trama. In the Hymenomycetes, or at least in the Agaricini, the stem is continued from the mycelium at right angles, as in the moulds, and is‘compounded of an infinity of elongated parallel cells; these are sometimes deficient in the centre, and the carpophore, or stem, becomes hollow. Leaving the appendages to the stem out of question, it is still an erect carpophore, and hence its func- tions are the same—that of elevating the re- Fic. 10.—Inflat- productive organs into the atmosphere. In ©@ carpophore the same manner also the materials of nutrition, derived by the mycelium from the soil, are conveyed upwards to the residue of the plant. The veil, where it exists, is a supplementary appendage, not found in the moulds, and is THE CARPOPHORE 25 simply an extension of the margin of the receptacle, or pileus, for the projection of the young hymenium. In Boletus and the stipitate Polyporei, Hydnei, etc., the carpophore is of the same type. In such of the species of Plewrotus, Fomes, etc., as have no stem the pileus, or receptacle, is sessile, and the carpophore is reduced to a mere disc, or is obsolete. The external surface of the stipe or stem is sometimes glutinous, as in the section Myxaciwm of the genus Cortinarius ; or it is velvety, as in such species as Collybia longipes and C. velutipes ; or it may be woolly, chiefly at the base, or broken up into scales; and all these conditions doubtless serve in some way to fulfil some purpose. Worthington Smith has suggested that they are probably of service to arrest the spores as they fall from the hymenium, and, as he thinks, also the deciduous cystidia. Of the internal structure M. de Seynes remarks that the collective cells, which form the stipe, and afterwards expand into the cap, are generally rather uniform, long, fibrous, often much separated, rarely ramified, presenting at times in their distance from each other, at others in their dimensions, differences which, on the fissure of the stipe, present an aspect either fibrous, granulated, spongy, or woolly. The cellular fibres are always closer and more compact at the cortical part. Those peculiar lactiferous vessels which convey the milk, so conspicuous in Lactarius, are not confined to the cap, but are present also in the stem, although possibly not quite so abundant, but they must be very numerous in the stems of one section of the genus Mycena where the milk is almost confined to the stem. In Mycena leucogalus it is quite white, in Mycena haematopus, of a blood red; in Mycena crocatus it is saffron yellow, and in Mycena galopus it is described as white, but it is often watery, or with a tinge of white, like milk and water. The quantity of milk depends much on the dampness of the habitat. In such degraded forms as Corticiwm, Radulum, etc., the carpophore is obsolete, and the receptacle is reduced to a fibrous stratum, which is seated directly upon the mycelium, and only the hymenium receives its proper development. Other genera require little observation, since in some forms of Thelephora, in Lachnocladium, and in Clavaria and its allies, 26 INTRODUCTION TO THE STUDY OF FUNGI we have the closest resemblance to the carpophores of the moulds, even to dendritic branching, but of a larger and more robust habit. Jsaria is often closely imitated in external appearance by Clavaria.. The most anomalous of all groups in respect to the carpophore is the Zemellini, but even in this there is a link in Gwepinia, Gyrocephalus, and Ditiola. We have not forgotten that in some of the Basidiomycetes the whole of the Fungus, in its earliest stage, when seated upon the mycelium, and before the development of the carpophore, is enveloped in a volva. This is not, however, more than a generic distinction, in any case, and reaches its highest de- velopment in Amanita, Volvaria, Ithyphallus, Clathrus, ete. It might be compared to the calyptra in mosses and liver- worts, but is by no means so general, and without so much significance. The Gastromycetes are not so well provided with a carpo- phore as the Hymenomycetes, but at the same time there is no degradation to resupinate or overturned forms. The majority of the Phalloid Gastromycetes have a distinct carpophore, which is functionally the same as in Agarics, but the structure is more loosely cellular (Fig. 11), and, from rapidity of growth, lacunose. It is only in Fungi like these, which are quick to decay, that we encounter such a loose texture of cells in the carpophore. In Podaxis the form of the entire plant resembles that of Coprinus, but the carpophore is rigid, almost woody, as it is also in Batarrea, Xylopodium, and Tylostoma. The carpophore in Secotiwm approaches * the type of the coriaceous Agaricini, such as oa haere Lentinus. There are no other genera which call Ithyphallus for special notice respecting the carpophore, which impudicus. +s short, and almost spurious in Scleroderma and Polysaccum, rare in Lycoperdon, and then only a prolongation of the spongy base of the receptacle. In nearly every genus except Gyrophragmium, Podaxis, and Secotiwm, it expands into, and is confluent with the receptacle. The subterranean species, like the truffles, have no carpophore. It is not difficult to comprehend the functions of the THE CARPOPHORE 27 carpophore in the Hymenomycetes, in all of which the hymenium is inferior, and therefore it is essential to its development that the receptacle should be raised sufficiently above the matrix to permit of a free development of the hymenium. The carpophore is only suppressed or obsolete when the receptacle ‘grows out at right angles to the matrix, and then no stem is essential. Furthermore, so many species grow on vegetable debris and dead leaves, hence a stem is necessary to push the puleus into the light. All collectors know how much the stems are lengthened beyond their normal proportions when the mycelium is deeply imbedded in the loose soil, and that the hymenium is not developed until the pileus is elevated into the light. In the Gastromycetes the hymenium is not inferior, so that it is sufficient if the receptacle is just above the soil, and hence the carpophore is short. The Phalloidei are exceptional, as the hymenium is not concealed, but must be well exposed, in order to mature speedily. All the remainder of the large fleshy Fungi belong to the Discomycetes, in which the hymenium is exposed on the upper surface, and therefore, as might be expected, the carpophore is often short or absent. The Morels and Helvellas are all stipitate, and the receptacle is lke a cap or hood; but as they are terrestrial, often grow- ing in loose soil and amongst debris, a carpophore long enough to bring the receptacle into the light is essential. In this case the substance scarcely differs from that of the cap, but it is robust, and the external stratum is not car- tilaginous. In several genera of ter- i ene A -restrial habit the form is clavate, with 9" of peciza. a carpophore long enough to bring the hymenium through the short grass into the light, just as in simple club-shaped forms of Clavaria. We need only to allude to the old genus Peziza, whatever the modern designation may be, for all of the species are cup-shaped in form (Fig. 12), and the hymenium is turned to the light, hence all the carpophore which is necessary is that which is sufficient for such a purpose, 28 INTRODUCTION TO THE STUDY OF FUNGI so that usually the carpophore is short, and often reduced to a mere point. Species such as that which grows on the sclerotium of anemone roots are variable in the length of the carpophore in proportion to the depth at which the sclerotium is buried, or of such as grow on acorns or beech-mast lying on the ground the carpophore is long enough to bring the hymenium to the light. Peziza aurantia or Pezza badia, growing on naked soil, are fully exposed, and hence are sessile. Wherever, from its matrix or peculiar habit of growth, a species, if sessile, could not expose its hymenium to the light under ordinary circumstances, a carpophore is usually present. Species which grow beneath the bark of branches, and break through, have invariably a short carpophore to raise the disc to the surface. Some special forms of carpophore are to be found in the Pyrenomycetes, where the fructification is capsular, and the receptacle small and simple. In this case the carpophore is not, except rarely, that of a single individual, but of a colony or an agglomeration of individuals, each individual being represented by the fruit receptacle, the carpophore being a vegetative branch, developed from the mycelium, specialised to carry the fruc- tification, as the conidiophore of a mould is specialised to carry a great number of conidia. For example, the pupa of a moth becomes filled with mycelium, which, in the first instance, developed 2 conidia under the form of Jsaria farinosa (Fig. 13); 1g. 13.—Tsa- / ria farinosa finally, a club-shaped fleshy protuberance called se of a stroma grows from the surface of the pupa in connection with and continuation of the internal mycelium. This fleshy stroma is at first only a sterile branch from the mycelium, like the stem of an Agaric, but ultimately the whole of its upper surface is covered with an indefinite number of minute receptacles, which are developed in a colony at the apex of a carpophore. The insects, whether larvae or pupae, on which these Fungi are developed are at the time buried in the soil, and the function of the carpophore is to carry the fructification into the light, so that sometimes it has to be prolonged several inches before THE CARPOPHORE 29 the fructifying surface is sufficiently raised above the soil to attain its development (Fig. 14). The carpophores vary not only in length for the same species, according to circumstances, but also in form, according to the species. In some it is simple, and in others branched, but the receptacles are always densely accumulated about the apices in this genus of Cordyceps. Hence we recognise again that a carpophore is a contrivance which is resorted to in order to bring the fructification into the air and light, and is lengthened or shortened in con- formity with that object. In the genus XYylaria the form of carpophore is similar, but its texture different. The colour is normally black exter- nally, white and corky within, and it is wholly tough and hard. The species grow on putrid Fic. 14.—Clav- wood and rotting leaves. In an allied genus, ## Stroma of : ordyceps. Thamnomyces, the carpophore is very long and thin, often like horse hair, running amongst dead leaves and vegetable debris. It is notable how some of the simplest forms of carpophore are repeated in different groups of Fungi far removed from each other in structure. This is the case where the whole Fungus is club- shaped, as it is in Clavaria pistillaris, and again, even as to colour, in Yylaria involuta. Others of a smaller size, but of a like form, will be found in Clavaria ligula, Leptoglossum olivaceum ; Xylariva \ Y\\/ rhopaloides ; Geoglossum hirsutum, and v/ ) \\ tA Hypocrea ophioglossordes. VI 2 Wed No one can doubt, after tracing the Fic. 15.—Globose stroma of oradations of form in Xylaria, that the Hypoxylon. . : spherical carpophores, not only in Aylaria, but also in Daldinia, Glaziella, Sarcoxylon, and the Sphaeroxylon section of Hypoxylon, are of the same character, and have a similar purpose to the foregoing (Fig. 15). Possibly the globose forms may primarily serve to expose the largest surface of immersed receptacles to the light, rather than elevate 30 INTRODUCTION TO THE STUDY OF FUNGI them from darkness into light, as was seen to be the first function of the long-stemmed carpophores. Everything indicates in the Pyrenomycetes that there is some necessity for exposing the fructifying surface to the light; whether on carpophores or effused in a stroma, only one stratum of perithecia is the rule, a double series the very rare exception. CHAPTER IV THE RECEPTACLE Havine described the mycelium, already designated as the vegetative Fungus, and which is always present, we passed to an outgrowth of the mycelium (sometimes suppressed), which, as the carpophore, is destined to support the receptacle, It is the latter which contains the fructification, or, in the case of naked fruits, supports the fructification itself. It may be urged that the receptacle is part and parcel of the fructifica- tion, but it is really no more intimately so than are the receptacle or the calyx and corolla in flowering plants. This, however, need not be discussed, as it is only a question of analogies. What we desire to include under the present designation is the development, or modification, of the superior continuation of the carpophore, which encloses or supports the essentials of fructification. In the absence of any distinct or evident carpophore, it is still the immediate supporter or envelope of the fructification, which in that case is sessile upon the mycelium. This receptacle may be variable in form, and be known under different designations, but its function is the same— that of supporting or enclosing the hymenium, wherever a hymenium or its analogue is present. This organ will be represented in some cases by a pileus, in others by a peridium, an excipulum, a perithecium, a sporangium, or even a proliferous stratum. The best-known form, because the largest and most con- spicuous, is the pilews, which is characteristic of the Hymeno- mycetes. It forms the cap in Agarics and the pileus in Fomes, Polystictus, etc. This cap in Agarics and allied genera 32 INTRODUCTION TO THE STUDY OF FUNGI surmounts the stem or carpophore, and bears on its under sur- face the hymenium or fructiferous surface. It follows the same type in the Agaricini, Boleti, some Polyporei, and Hydnei. This type is a convex, or primarily convex, orbicular expansion of the apex of the stem, with a more or less distinct pellicle on its upper surface, an intermediate stratum, and its lower sur- face covered by the hymenium. In this type, then, it is a hymenophore, as it is in other forms of Hymenomycetes. This cap (Fig. 16) not only surmounts, but it is continuous with the stem, and for the most part conforms to it in texture. In some cases it passes down in plates on the under surface between Fic. 16.—Agaric. A, young; B, mature; C, section; p, pileus ; s, stipe ; v, volva; g, lamellae or gills ; a, annulus or ring. the folds of the membrane which bears the hymenium, and is the trama. The superior cuticle or pellicle is sometimes so distinct from the subjacent stratum that it may be stripped off, but in other species it is so intimately incorporated with the substratum that it is inseparable. From the margin of the cap this cuticle is sometimes extended inwards and united to the stem, covering the young hymenium, and forming a veil. Externally the cuticle may be quite dry or viscid, or even covered with a slimy gluten, as in Agaricus mucidus and Agaricus aeruginosus. In some cases the cuticle is compara- THE RECEPTACLE 33 tively thick, and consists of an outer and inner layer, the former breaking up as the cap expands, and adhering in patches or scales, as in Agaricus procerus, whilst the inner silky, fibrous layer is closely adnate to the flesh. Not uncom- monly the cuticle, without breaking up, is finely striate with innate silky fibrils, or shining with a satiny lustre. The flesh beneath the cuticle differs somewhat in different species, in texture and in comparative thickness, but is always thinnest about the margin, sometimes scarcely exceeding that of the cuticle. The cells of the fleshy substance of the pileus in Agarics are more branched than those of the stipe. They will form, by anastomosing and crossing each other, a sort of poly- gonal trellis-work, and in the meshes so formed there is a second system of larger cells. Corda alludes to them, especially in the Russulae, and he says, “ These two forms are not always neatly separated, but pass, as the organ requires, more or less rapidly, one into the other, or, what is more rare, they are sub- stituted the one for the other. These two forms of tissue take part, generally both together, in the structure of the hymenium, each giving birth, or both together, to one or many organs of the hymenium.” * The lactiferous tubes in such a genus as Lactarius are often of larger dimensions than the ordinary tissue, and M. de Seynes protests against their being called “ vessels,” because, if the cells are very long, yet it is possible to see that they are divided transversely. In Fistulina, which contains an abundant red juice but more fluid, it is contained in special varicose and sinuous tubes, like the laticifers, but furnished with transverse divisions. On approaching the gills the same series of cells are curved and recurved, showing that the milky secretion is there more abundant. As to the functions or import of this juice, that is still an obscure point, for there are so very many Agarics which do not possess it at all, or if pre- sent, it is in smaller quantity, and not equally visible. It is well enough known that in Lactarius the milky juice descends into the hymenium, for if the gills are cut or bruised, it oozes out, and hangs suspended in drops. When dried it is readily seen to be resinous. 1 Corda, Icones Fungorum. 3 34 INTRODUCTION TO THE STUDY OF FUNGI No one has yet paid much attention to the coloration of the pileus in Agaricini, which is subject to much variation, due in part to external circumstances, as was pointed out by M. de Seynes. Albinism is one of the variations which he observed in well-recognised species. It occurs in Hygrophorus calyptraeformis, Amanitopsis vaginata, Russula fragilis, and some others. “By the side of this fact there is another quite opposite, the greater intensity of coloration, according to the temperature.” For instance, he found during the winter Tricholoma nuda, according as the temperature falls, of a dark violet, almost black, or a deep brown. When spring arrives it is found almost white, shaded with lilac or fawn colour. Tricholoma terreus and Collybia dryophilus will present the same phenomena. He found also, in a cold December, Volvaria media of which the pileus was almost black; ordinarily it is nearly white. Upon microscopical examination he found that there was no new production of cellular elements, but simply a greater agglomeration of pigmentary granules. He also indicates that he has often been struck with the deep colora- tion of Armillaria mellea and Hypholoma sublateritius, which were seen by hundreds during a low temperature (41° to 42° Fahr.), the aspect of which differed very much from the same species found in the woods during the fine days of autumn.’ The same writer adds that, from numerous observations, he is certain that, although the cold has an influence upon the intensity of coloration amongst Agarics, it does not follow that in the middle of winter specimens may not be found of the normal colour, either by being shaded, or in proximity to heat. The effects of external circumstances on the variation of the fleshy Fungi deserves more serious attention. In some few instances the fleshy stratum is almost obsolete over the entire cap, as in. Hiatula, some species of Coprinus, Bolbitius, etc., and in some exotic species of Marasmius. In such cases the cap is so thin—like a membrane—that when moist the gills may be seen through the substance. In Boletus the cuticle is sometimes distinctly velvety, and the flesh is comparatively thicker than in Agarics. In Polyporus, Fomes, Polystictus, Hydnum, ete., the entire substance is more 1 Grevillea, vol. ii. p. 12. THE RECEPTACLE 35 woody, contains less moisture, and consequently dries with but little shrinking or change of form. As the carpophore is sometimes obsolete in the Hymeno- mycetes, so also is the receptacle or pileus reduced to a simple stratum, which intervenes between the mycelium and the spore-bearing surface. These are undoubtedly rudimentary forms, but they are very numerous, sometimes constituting entire genera, as in Poria, Coniophora, Corticiwm, etc., besides numerous species in other genera. For the most part a thin fibrous stratum, differentiated from the fibres of the mycelium, forms, and supports the hymenium. Possibly the old genus Ozonium consists entirely of these suppressed pilei, which never form a hymenium. The supporting stratum is very peculiar in Asterostroma, where the hyphae are stellate, and in Thele- phora pedicellata they assume a dendritic form. It is not uncommon to find specimens of Corticiwm in which the hymenium is only in patches, or, in some cases, never formed at all, so that the whole Fungus remains in the vegetative stage, that is to say, mycelium, and a sterile fibrous stratum to represent suppressed carpophore and atrophied receptacle. The second type is deficient in any appreciable carpophore or stem, and con- sists of a pileus of a semicircular out- line, attached at its base to the matrix and its own my- celium (Fig. 17). In these also there is a superior stra- tum, which may be thicker than in the preceding, an inter- mediate substance, and an inferior hy- Fic. 17.—Vistulina hepatica, sessile pileus. menium. The upper stratum in Polyporus and Fistulina is hardly distinct from the intermediate; but in Fomes it usually forms a firm hard crust, very hard and horny in fomes australis and 36 INTRODUCTION TO THE STUDY OF FUNGI Fomes cornu-bovis, but smooth, and mostly shining, often laceate, as if varnished. According to Wettstein,’ this is due to the secretion of resin which oozes from peculiar hyphae and flows over the surface of the pileus. The exterior of the pileus exhibits deep concentrated channels, which mark the annual additions at the circumference. The substance is often very thick and fibrous, the fibres radiating in every direction from the base. They may continue growing by the addition of external zones for many years, always the oldest posteriorly. From these Polystictus differs in being much thinner, and the cuticle is fibrous, hairy, woolly, or strigose, and concentrically zoned. The substance is dry, tough, and leathery, usually flexible. In so far as these features are concerned, Sterewm not only resembles Polystietus in appearance, but also in texture, and so does Hymenochaeie ; whilst Hexagona differs more in the hymenium than in anything else. These, therefore, may be accepted as representing the two forms of the sessile receptacle in Hymenomycetal Fungi—the woody by Fomes, to which might be added Daedalea, and the coriaceous by Polystictus, and the others above named. The next form of receptacle to be adduced is the peridium, which completely encloses the reprotluctive organs, and may also be supported on a distinct carpophore, or it may be sessile on the mycelium, or invested by it, as in some subterranean species. The Gastromycetes furnish this kind of receptacle, which is very often double, typically globose, the outer coat or exoperidium being a continuation of the cortex of the carpophore when the latter exists. The internal cavity is filled with the reproductive bodies, which are only liberated by the rupture of sis the coat of the peridium. The inner Fic. 18.—Lycoperdon, peridium coat or endoperidium is often thin and enna membranaceous, and may either be wholly separated from the outer or adnate therewith (Fig. 18). A prolongation from the carpophore sometimes protrudes into the central cavity in the form of a columella. The outer coat or 1 Verhand. Zool. Bot. Gesell., Wien, xxxv. (1886), p. 29. THE RECEPTACLE 37 exoperidium may be tough and leathery, and in Geaster it splits downwards from the apex into several triangular lobes. In Bovista it is fragile and evanescent. In Lycoperdon it breaks up into granules, warts, or spines, which adhere for some time to the inner and persistent peridium. In Polysaccum and Scleroderma the periderm is not differentiated into two coats, but in the latter the exterior cracks into warts or frustules. In this form the receptacle is an entirely closed envelope, in which the fructification is completely concealed until it is quite mature, and then it either opens with a small orifice or is irregularly ruptured. Hence the light is not essential to the perfection of the fruit, and the peridium might almost as well remain in the soil, which it has a tendency to do in some species of Scleroderma, and does completely in the Hypogaet. In the majority of species the substance of the peridium is tough and leathery, and so persistent that it often remains behind long after dehiscence and the dispersal of the spores. A third form of receptacle is the excipulum or cup-shaped receptacle, which, although often closed when young, is soon expanded so as to expose the disc or hymenium to the full light; in fact they are heliotropic, for they turn the disc as much as possible towards the sun. The type of this form is to be found in the old genus Peziza, now split up into many genera, but the form and structure of the excipulum is the same throughout (Fig. 19). The external stratum of cells does not form a separate cuticle, but is continuous with the subjacent cells, and usually consists F!¢-19.—Receptacle of Peziza, 5 with section and ascus. of smaller or elongated cells, which may be coloured, and either mixed with or prolonged into hairs, usually most strongly developed about the margin of the excipulum. Within the cuticular layer lie the subhymenial cells, on which rests the hymenium or fruit-bearing surface. The attributes of this form, therefore, are a cup-shaped receptacle, with the mouth turned to the lght, and composed of an external and internal series of cells, the latter supporting 38 INTRODUCTION TO THE STUDY OF FUNGI a compact hymenium. The substance of the cup and entire Fungus is most often soft and fleshy, and therefore they are more or less hygrometric, closing when dry and expanding when moist. Whether naked or clothed with hairs, the exterior is usually dull and sombre-coloured, so as scarcely to be distinguished from the matrix on which they grow. A similarly-shaped receptacle is to be found in Cyphella amongst the Hymenomycetal Fungi, in Cyathus and Crucibulum amongst the Gastromycetes, and in