A monograph of cantharelloid fungi

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ANNALS OF BOTANY MEMOIRS No.

2

A MONOGRAPH OF

CANTHARELLOID FUNGI

A MONOGRAPH OF

CANTHARELLOID FUNGI BY

E. J. H. CO R N E R, F.R.S., F.L.S. Professor of Tropical Botany Cambridge

OXFORD UNIVERSITY PRESS 1966

Oxford University Press, Ely House, London W. I GLASGOW NEW YORK TORONTO Ml!LBOURNE WELLINGTON

CAPE TOWN SALISBURY IBADAN NAIROBI LUSAKA ADDIS ABABA BOMBAY CALCUTTA MADRAS KARACHI LAHORE DACCA KUALA LUMPUR HONG KONG

© Oxford University Press I966

PRINTED IN GREAT BRITAIN AT THE UNIVERSITY PRESS, OXFORD BY VIVIAN RIDLER PRINTER TO THE UNIVERSITY

CONTENTS L I ST O F PLAT E S

page vii

I N TR O D U CT I O N 2

Definition of Cantharelloid Fungi Pileus

3

Gill-folds

5

Basidia

9

Spores

15

Cystidia

15

Hyphae

15

Affinity of Genera

16

Supra-generic Names

21

KEY TO G E N E RA O F CANTHARELLO I D FUN G I ARRHEN I A CA N TH A R ELLULA

( and

PsE U D O CLJTO CYBE)

C A N T H A R ELLU S CA R I P I A C R A T E R ELL U S DIC H A N T H A R ELLU S GE OPETALU M

102

GLO E O C ANTH A R ELLU S

III

GOMPHU S

1 12

GoossENS I A H Y G R O P H O R OPS I S L EPTO GLO S S UM MYCENELLA NYCTALIS PSEVD O C R A T E R ELLU S PTE RYGELLU S RJM B A C H I A

172

T R O GIA

175

vi

CONTENTS

G E N E R A L B I B L I O G RAPHY

2 45

I N D EX T O G E N E R A, S P E CIE S, V A R I E T I E S, A N D SYNONYMS

2 47

P L A T E S 1 -5

at end

LIST 0 F PLATES At end PLATE I. A, Cantharellus formosus Comer. B, Cantharellus subcibarius Comer var. sordidus Comer. c, Cantharellus ianthinus Comer. o, Cantharellus pudorinus Comer. PLATE 2. A, Cantharellus subcibarius Comer var. rugosivenis Comer. B, Pterygellus poly11Wrphus Comer var. minor Comer, the upper figures x 2. c, Hygrophoropsis flabelliformis (Berk. et Curt.) Comer. D, Pterygellus armeniacus Comer. E, Ptery­ gellus polymorphus Comer, x 2. F, Trogia ochrophylla Comer. PLATE 3 . A, Gomphus retisporus Comer. B, Trogia hispidula Comer var. bispora Comer. c, Craterellus verrucosus Massee. D, Cantharellus hystrix Comer. E, Canthar­ ellus sordidus Comer. PLATE 4. A, Trogia fulvochraua Comer, X 2. B, Trogia mycenoides Comer, x 3 . c, 'l'rogia straminea Comer. D , Trogia ceraceomollis Comer. E , Trogia anthidepas (Berk. et Br.) Comer var. saturatior Comer. F, G, Trogia anthidepas (Berk. et Br.) Corner, F young, G old. H, Trogia mellea Comer, x 2. PLATE 5. A, Trogia pleurotoides Comer. B, Trogia stereoides Comer. c, Trogia rivulosa Comer. D, Trogia cyanea Comer. E, Trogia ceraceo11Wllis Comer var. bispora Comer. F, Trogia subgelatinosa Comer. G, Trogia lilaceogrisea Comer var. bispora Comer. H, Trogia infundibuliformis (Berk. et Br.) Comer. 1, Trogia hispidula Comer. K, Dichantharellus malayanus Comer.

INTRODUCTION IT is now agreed that the Friesian classification of basidiomycetes is artificial and, for the world flora, unworkable. It was based on gross features which microscopic study has shown to be the result of parallel evolution as well as of common heritage. It mixed artificial grades and natural series. In its place, more fundamental methods are being de­ veloped by microscopic anatomy and microchemistry. Probably, how­ ever, because of the labour which these methods involve, not one-quarter of the world flora has been studied and confirmed in the necessary detail. Therefore, there is no alternative comprehensive classification. I met this problem in studying clavarioid fungi ( 1 950 ) . Clavaria and its allies Clavulinopsis and Ramariopsis have been put into the artificial Friesian family Clavariaceae along with such genera as Ramaria, Lachno­ cladium, and Pterula, which represent three different natural groups of the rank of .family or order. But a new supra-generic classification of clavarioid fungi cannot be made because its entities lead into other artificial families which have not yet been analysed. The facts can merely be dis­ played in more adequate generic arrangement for subsequent synthesis. Now, after many years, I offer a display of cantharelloid fungi. The Friesian idea is simple. They are toadstools with a pileus, but they lack the narrow, sharp, geotropic gills of the typical agarics. They have obtuse gill-folds, which often dichotomize and anastomose, or the hymenium is smooth without a trace of complication, as in Stereum. Microscopic study reveals many fundamental differences between the genera which have been grouped artificially as Cantharellaceae, and it reveals a fact barely notice­ able in clavarioid fungi. This is that several fungi put into Cantharellaceae are reduced agarics with small fruit-bodies from which the accurate gill mechanism has been lost. The point has long been known. For over three generations mycologists have been transferring such cantharelloid fungi to their immediate affinity in Agaricales, leaving as a nucleus of Cantharellales Cantharellus and Craterellus. Thus, the idea has sprung up that cantharelloid fungi repre­ sent two extremes. Some genera such as Cantharellus and Craterellus are primitively simple and on the way, as it were, to developing agaric gills from the smooth hymenium of clavarioid and thelephoroid fungi ; other genera such as Caripia and Leptoglossum are secondarily simple, as agarics losing the gill mechanism. The view is expressed by Singer in his classification of Agaricales ( 1 962). Several of the genera, which I include here, are disposed by Singer among six or seven tribes of Agaricales in the 854358

B

2

INTRO D UCTION

families Polyporaceae and Tricholomataceae, but Ca:ntharellus and Crater­ ellus are excluded. In the enthusiasm for betterment, his classification goes beyond the bounds of understanding, when it expects the botanist to look for Polyporus, Caripia, Physalacria, Amanita, Russula, and Boletus in the same order. The question, then, arises whether all cantharelloid fungi may not be degenerate agarics. It is an assumption that, in the evolution of basidio­ mycetes, a smooth hymenium was primitive and that by subsequent complication under a protecting pileus, gills, pores, and spines were evolved. The alliances of Clavariadelphus and Ca:ntharellus and of Ramaria and Gomphus may be cited as instances. But the fact is that many polyporoid, hydnoid, and agaricoid genera have been found to have de­ generate species, or allied genera, with more or less cantharelloid or smooth hymenium. When the alliance of Clavariadelphus or, as some prefer, Ramaria with Ca:ntharellus is reconsidered in this light, the issue is by no means clear (p. 1 9). The truth is that there is no adequate theory of basidiomycete evolution, and there cannot be until the fungi of the tropics are better known than those of western Europe. In the immense tropical variety, there must be many clues, both abundant and rare, as yet un­ conceived. I mention Dicha:ntharellus with cantharelloid hymenium, stereoid habit, agaricoid texture, Lachnocladium dichophyses, and gloeo­ cystidial hymenium. I mention Ca:ntharellus fuligineus which seems at sight to be the link between Cantharellus and Craterellus. And I mention Trogi,a to show that there is not yet the knowledge for a major classifica­ tion of any kind of homobasidiomycete. Trogia has a unique microscopic structure which parallels in the gross form of the fruit-body Cantharellus, Craterellus, Lentinus, Pleurotus, Cutocybe, Omphauna, Mycena, and Stereum. I am led to believe that the cantharelloid fungi are most critical for the understanding of homobasidiomycetes. As with clavarioid fungi, therefore, I present the cantharelloid as another easily recognizable assemblage. I have had in mind particularly the tropical mycologist, and have provided keys to the species of the world, so far as possible. If I may judge from the interest awakened in clavarioid fungi, another need is fulfilled. -

DEFINITION OF CANTHARELLOID FUNGI Homobasidiomycetes with pileate, gymnocarpic, agaric-like fruit-bodies ; fleshy, putrescent, not perennating or reviving after desiccation. Stem sterile or fertile only at the apex. Hymenium smooth or folded with radiating, often anastomosing and branched, obtuse ridges, restricted to the surfaces of the stem and pileus with a downward component. Hyphae inflating acropetally and directly.

The important points are the presence of a pileus with sterile upperside, developed by marginal growth from the stem apex, the obtuse gill-folds,

D E F I N I T I O N O F C A N THAR E L L O I D F U N G I

3

and the fleshy consistency. The first distinguishes the cantharelloid from the clavarioid fungi, which may have a sterile upperside to the club (Araeocoryne, Clavariadelphus subgen. Cantharellopsis). The second dis­ tinguishes them from Agaricales in general. The third distinguishes those cantharelloid fungi with smooth hymenium from Thelephoraceae (mostly with thick-walled, uninflating hyphae).

\

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r \

\

\

\ FIG.

\ \

\j

\

\

\

\\

\

\

�

l. Cantharellus formosus (left), with well-developed gill-folds, X l!. C. pudorinus (right), with almost smooth hymenium, X f; the two young stages, X l!.

PILEUS

The pileus is an expansion of the stem apex which develops into a diageo­ tropic, umbrella-shaped or fan-shaped form. The margin of the pileus is incurved by epinastic growth, which results from the more rapid inflation of the cells on the upperside. Eventually as the hymenium enlarges, the margin is straightened and the pileus is forced into a plane, concave, or funnel-like form. Exceptions are Craterellus, Pterygellus, Dichantharellus, Leptoglossum, Rimbachia, and some species of Trogia. In the last three, the straight margin may be secondary and result from the loss of form factors in the degenerating agaric fruit-body. This may be the case, too, with Craterellus, but Dichantharellus and Pterygellus seem to have the direct marginal growth, without epinasty, characteristic of pileate Thele­ phoraceae.

4

I N T R O D U C T I ON

FIG. 2. Cantharellus pudinorinus: diagram of the structure of the pileus mar­ gin, the hyphae on the upper side more strongly inflated than on the lower side above the hymenium, x 5 0; the shallow gill-folds in transverse section to show the loose tramal tissue, X 25.

The assumption of diageotropic growth by the stem apex is usually gradual. This change in direction of growth accentuates the funnel shape and gives to it an apparently primitive form, compared with the more or less umbonate, or initially convex, shape of the agaric pileus, for in this there is an abrupt diageotropic (or diaphototropic) change in direction of growth.

PILEUS

FIG. 3 .

s

Cantharellus infundibulijormis : characteristic hyphae from the margin of the pileus, x 250.

GILL-FOLDS

The folds are lines of excessive intercalary growth of the initially smooth hymenium. It is thrown, thereby, into obtuse ridges radiating from the stem apex towards the pileus margin along the direction of hyphal growth.

6

INTRODUCTION

The folds may b e irregular and anastomose at lengthy intervals so as not to give a poroid appearance (except in Rimhachia), or they may be regular and, then, either repeatedly and regularly dichotomous to fill the widening intervals between them as they radiate, or pinnately arranged with second-

B

c

D

FIG. 4.

Cantharellus injundibuliformis: diagrams of the development of the primordium, X 40. A, the primordial shaft. B, the apex of the shaft thickening on cessation of its centralized apical growth. c, the initiation of the pileus by a dead space over the centre. D, the beginning of marginal growth of the pileus to form the limb.

ary folds in rankS, similar to the construction of agaric gills. No simple mechanical theory of folding can account, however, for such regularity which clearly depends on some organization of a gill-field in the incipient hymenium, similar to the pore-field of polypores (Corner, 1 932). This abstruse process causes in cantharelloid gill-folds not the outgrowth of gill hyphae to form a new tramal plate suspending the new hymenium, but merely the more abundant intercalation of new basidia from the sub­ hymenium. Thus, the gill-fold has an obtuse fertile edge from the outset, and it lacks a regular trama ; in fact, such trama as there is consists of the hyphae from the lower part of the pileus pulled out in various directions as their basidial connexions are separated in the expanding hymenium ; eventually there may be merely a loose weft of hyphae or, even, a micro­ scopic gap at the junction of fold with pileus. In some species, such as Cantharellus infundibuliformis, continued inter­ calary growth of the hymenium may deepen the fold to a height of 3 mm, or even 7 mm in the African C. cyanoxanthus. There is, however, another factor which adds to the obtuse form of the fold. It is the continuous thickening of the hymenium by continual outgrowth of new basidia over­ topping the old which, if they do not dissolve away, may be detected within the old hymenium ; it is the feature of the thickening hymenium, found in many clavarioid and stereoid fungi (Corner, 1 950, p. II). Thus, the gill-fold deepens by intercalary growth and thickens by basidial outgrowth.

G I L L -FO L D S

7

Fm. 5 . Cantharellus infundibuliformis : diagrams of the development of the pileus with incurvature of the margin, X 40. B with immature, F with maturing, basidia.

agaric gill, formed by definitive outgrowth of hyphae more or less at right angles to the direction of the hyphae in the pileus ; its edge is sterile, at least while in active growth, and, as in all agarics, the hymenium is precisely constructed from a single layer of basidia, the new being inserted between the old without overtopping. The thickness of the gills in Hygrophorus

8

INTRODUCTION

is caused mainly by the strong inflation of the descending tramal hyphae, and this resemblance with the cantharelloid gill-fold is largely spurious. Unfortunately, the criteria become blurred through the loss, apparently, of hymenial thickening in some small fruit-bodies of Cantharellus, and the

FIG. 6.

Cantharellus inconspicuus: the slightly incurved, attenuate margin of the nearly full-grown pileus,

X

400.

loss of gill outgrowth in degenerate agarics. Nevertheless, the construction of the gill is the chief distinction between Cantharellus and Hygrophorus, other than the problematic question of the direction of the nuclear spindle of meiosis (p. 9). In several cantharelloid fungi the hymenium is smooth. The absence of gill-folds from large fructifications, such as those of Cantharellus odoratus, may be considered primitive. The absence from small fructifications, such as those of C. atratus, may be secondary through loss of form factors. Indeed, the diverseness of the pairs of allied species with and without gill­ folds indicates that, in general, the smooth hymenium is secondary and that these present-day gill-less species are not to be interpreted as primi­ tives. Examples are Canth .. cibarius-C. odoratus, C. infundibuliformis­ C. lutescens, Gomphus flabellatus-G. stereoides, and several instances in Trogia (p. 1 80), just as they occur in Laccaria, Marasmius, Omphalina, and other agarics. In these cases, as shown by Trogia, the species with

G I L L - FO L D S

9

well-developed gills form them by tramal outgrowth from the pileus, but as the stimulus for outgrowth declines, so narrow gills, cantharelloid folds, and finally, with total loss of stimulus, the smooth hymenium result.

FIG. 7.

Pterygellus polymorphus: the straight margin

of the pileus, x 400.

Another form of gill-fold is shown by Craterellus and Pterygellus. It appears so different that it could be used to define a separate family ; yet, there is evidence that this manner of making radiating gills occurs also in some species which have been placed in Lentinus and Panus. The apparent fold is formed by radial thickening of the tissue of the pileus which there­ fore projects the hymenium along the line of tissue thickening. As the hymenium also thickens in Craterellus and Pterygellus, the obtuse fold is superficially identical with that of Cantharellus, but microscopic study shows that the folded hymenium is reinforced by a radiating strand of hyphae parallel to those of the pileus, not descending at right angles as in agarics. Such false gill-folds, or hymenial ribs, in Pterygellus may be radially dichotomous or pinnately branched, which is a unique construc­ tion in basidiomycetes. In Pterygellus polymorphus the ribs may be present or not, and this species shows again how the form factors may be lost and confer on present-day fungi a false primitiveness. BAS ID IA

It is well known that the basidia of Cantharellus, Craterellus, and Pseudo­ craterellus are typically long and narrow. In Canth. cibarziu, Grat. cornu­ copioides, and Ps. sinuosus they are stichic with longitudinal meiotic spindle (Juel, 1 9 1 6). It has become customary to assume that all species of these genera have stichic basidia with longitudinal spindle, in contrast to the

F10. 8.

Craterel/us cornucopi