Fungi: Their Nature and Uses Part 23

Unfortunately no complete or satisfactory account can be given of the geographical distribution of fungi. The younger Fries,[A] with all the facilities at his disposal which the lengthened experience and large collections of his father afforded, could only give a very imperfect outline, and now we can add very little to what he has given. The cause of this difficulty lies in the fact that the Mycologic Flora of so large a portion of the world remains unexplored, not only in remote regions, but even in civilized countries where the Phanerogamic Flora is well known. Europe, England, Scotland, and Wales are as well explored as any other country, but Ireland is comparatively unknown, no complete collection having ever been made, or any at least published. Scandinavia has also been well examined, and the northern portions of France, with Belgium, some parts of Germany and Austria, in Russia the neighbourhood of St. Petersburg, and parts of Italy and Switzerland. Turkey in Europe, nearly all Russia, Spain, and Portugal are almost unknown. As to North America, considerable advances have been made since Schweinitz by Messrs. Curtis and Ravenel, but their collections in Carolina cannot be supposed to represent the whole of the United States; the small collections made in Texas, Mexico, etc., only serve to show the richness of the country, not yet half exhausted. It is to be hoped that the young race of botanists in the United States will apply themselves to the task of investigating the Mycologic Flora of this rich and fertile region. In Central America very small and incomplete collections have as yet been made, and the same may be said of South America and Canada. Of the whole extent of the New World, only the Carolina States of North America can really be said to be satisfactorily known. Asia is still less known, the whole of our vast Indian Empire being represented by the collections made by Dr. Hooker in the Sikkim Himalayas, and a few isolated specimens from other parts. Ceylon has recently been removed from the category of the unknown by the publication of its Mycologic Flora.[B] All that is known of Java is supplied by the researches of Junghuhn; whilst all the rest is completely unknown, including China, j.a.pan, Siam, the Malayan Peninsula, Burmah, and the whole of the countries in the north and west of India. A little is known of the Philippines, and the Indian Archipelago, but this knowledge is too fragmentary to be of much service. In Africa no part has been properly explored, with the exception of Algeria, although something is known of the Cape of Good Hope and Natal. The Australasian Islands are better represented in the Floras published of those regions. Cuba and the West Indies generally are moderately well known from the collections of Mr. C. Wright, which have been recorded in the journal of the Linnaean Society, and in the same journal Mr. Berkeley has described many Australian species.

It will be seen from the above summary how unsatisfactory it must be to give anything like a general view of the geographical distribution of fungi, or to estimate at all approximately the number of species on the globe. Any attempt, therefore, must be made and accepted subject to the limitations we have expressed.

The conditions which determine the distribution of fungi are not precisely those which determine the distribution of the higher plants.

In the case of the parasitic species they may be said to follow the distribution of their foster-plants, as in the case of the rust, s.m.u.t, and mildew of the cultivated cereals, which have followed those grains wherever they have been distributed, and the potato disease, which is said to have been known in the native region of the potato plant before it made its appearance in Europe. We might also allude to _Puccinia malvacearum_, Ca., which was first made known as a South American species; it then travelled to Australia, and at length to Europe, reaching England the next year after it was recorded on the Continent. In the same manner, so far as we have the means of knowing, _Puccinia Apii_, Ca., was known on the Continent of Europe for some time before it was detected on the celery plants in this country.

Experience seems to warrant the conclusion that if a parasite affects a certain plant within a definite area, it will extend in time beyond that area to other countries where the foster-plant is found. This view accounts in some part for the discovery of species in this country, year after year, which had not been recorded before; some allowance being made for the fact that an increased number of observers and collectors may cause the search to be more complete, yet it must be conceded that the migration of Continental species must to some extent be going on, or how can it be accounted for that such large and attractive fungi as _Spara.s.sis crispa_, _Helvellas gigas_, and _Morch.e.l.la cra.s.sipes_ had never been recorded till recently, or amongst parasitic species such as the two species of _Puccinia_ above named? In the same manner it is undoubtedly true that species which at one time were common gradually become somewhat rare, and at length nearly extinct. We have observed this to apply to the larger species as well as to the microscopic in definite localities. For instance, _Craterellus cornucopioides_ some ten years ago appeared in one wood, at a certain spot, by hundreds, whereas during the past three or four years we have failed to find a single specimen. As many years since, and in two places, where the goat's-beard was abundant, as it is now, we found nearly half the flowering heads infested with _Ustilago receptaculorum_, but for the past two or three years, although we have sought it industriously, not a single specimen could be found. It is certain that plants found by d.i.c.kson, Bolton, and Sowerby, have not been detected since, whilst it is not improbable that species common with us may be very rare fifty years hence. In this manner it would really appear that fungi are much more liable than flowering plants to shift their localities, or increase and diminish in number.

The fleshy fungi, _Agaricini_ and _Boleti_ especially, are largely dependent upon the character of woods and forests. When the undergrowth of a wood is cleared away, as it often is every few years, it is easy to observe a considerable difference in the fungi. Species seem to change places, common ones amongst a dense undergrowth are rare or disappear with the copsewood, and others not observed before take their place. Some species, too, are peculiar to certain woods, such as beech woods and fir woods, and their distribution will consequently depend very much on the presence or absence of such woods. Epiphytal species, such as _Agaricus ulmarius_, _Agaricus mucidus_, and a host of others, depend on circ.u.mstances which do not influence the distribution of flowering plants. It may be a.s.sumed that such species as flourish in pastures and open places are subject to fewer adverse conditions than those which affect woods and forests.

Any one who has observed any locality with reference to its Mycologic Flora over a period of years will have been struck with the difference in number and variety caused by what may be termed a "favourable season," that is, plenty of moisture in August with warm weather afterwards. Although we know but little of the conditions of germination in Agarics, it is but reasonable to suppose that a succession of dry seasons will considerably influence the flora of any locality. Heat and humidity, therefore, are intimately concerned in the mycologic vegetation of a country. Fries has noted in his essay the features to which we have alluded. "The fact," he says, "must not be lost sight of that some species of fungi which have formerly been common in certain localities may become, within our lifetime, more and more scarce, and even altogether cease to grow there. The cause of this, doubtless, is the occurrence of some change in the physical const.i.tution of a locality, such as that resulting from the destruction of a forest, or from the drainage, by ditches and cuttings, of more or less extensive swamps, or from the cultivation of the soil--all of them circ.u.mstances which cause the destruction of the primitive fungaceous vegetation and the production of a new one. If we compare the fungal flora of America with that of European countries, we observe that the former equals, in its richness and the variety of its forms, that of the phanerogamous flora; it is probable, however, that, in the lapse of more or fewer years, this richness will decrease, in consequence of the extension of cultivation--as is ill.u.s.trated, indeed, in what has already taken place in the more thickly peopled districts, as, for example, in the vicinity of New York."

Although heat and humidity influence all kinds of vegetation, yet heat seems to exert a less, and humidity a greater, influence on fungi than on other plants. It is chiefly during the cool moist autumnal weather that the fleshy fungi flourish most vigorously in our own country, and we observe their number to increase with the humidity of the season.

Rain falls copiously in the United States, and this is one of the most fruitful countries known for the fleshy fungi. Hence it is a reasonable deduction that moisture is a condition favourable to the development of these plants. The _Myxogastres_, according to Dr. Henry Carter, are exceedingly abundant--in individuals, at least, if not in species--in Bombay, and this would lead to the conclusion that the members of this group are influenced as much by heat as humidity in their development, borne out by the more plentiful appearance of the species in this country in the warmer weather of summer.

In the essay to which we have alluded, Fries only attempts the recognition of two zones in his estimate of the distribution of fungi, and these are the temperate and tropical. The frigid zone produces no peculiar types, and is poor in the number of species, whilst no essential distinction can be drawn between the tropical and sub-tropical with our present limited information. Even these two zones must not be accepted too rigidly, since tropical forms will in some instances, and under favourable conditions, extend far upwards into the temperate zone.

"In any region whatever," writes Fries, "it is necessary, in the first instance, to draw a distinction between its open naked plains and its wooded tracts. In the level open country there is a more rapid evaporation of the moisture by the conjoined action of the sun and wind; whence it happens that such a region is more bare of fungi than one that is mountainous or covered by woods. On the other hand, plains possess several species peculiar to themselves; as, for example, _Agaricus pediades_, certain _Tricholomata_, and, above all, the family _Coprini_, of which they may be regarded as the special habitat. The species of this family augment in number, in any given country, in proportion to the extent and degree of its cultivation; for instance, they grow more luxuriantly in the province of Scania, in Sweden--a district farther distinguished above all others by its cultivation and fertility. In well-wooded countries moisture is retained a much longer time, and, as a result, the production of fungi is incomparably greater; and it is here desirable to make a distinction between the fungi growing in forests of resinous-wooded trees (_Coniferae_) and those which inhabit woods of other trees, for these two descriptions of forests may be rightly regarded, as to their fungaceous growths, as two different regions. Beneath the shade of _Coniferae_, fungi are earlier in their appearance; so much so, that it often happens they have attained their full development when their congeners in forests of non-resinous trees have scarcely commenced their growth. In woods of the latter sort, the fallen leaves, collected in thick layers, act as an obstacle to the soaking of moisture into the earth, and thereby r.e.t.a.r.d the vegetation of fungi; on the other hand, such woods retain moisture longer. These conditions afford to several large and remarkable species the necessary time for development. The beech is characteristic of our own region, but, further north this tree gives place to the birch. Coniferous woods are, moreover, divisible into two regions--that of the pines and that of the firs.

The latter is richer in species than the former, because, as is well known, fir-trees flourish in more fertile and moister soils.

Whether, with respect to the South of Europe, other subdivisions into regions are required, we know not; still less are we able to decide on the like question in reference to the countries beyond Europe."[C]

In very cold countries the higher fungi are rare, whilst in tropical countries they are most common at elevations which secure a temperate climate. In Java, Junghuhn found them most prolific at an elevation of 3,000 to 5,000 feet; and in India, Dr. Hooker remarked that they were most abundant at an elevation of 7,000 to 8,000 feet above the sea level.

For the higher fungi we must be indebted to the summary made by Fries, to which we have little to add.

The genus _Agaricus_ occupies the first place, and surpa.s.ses, in the number of species, all the other generic groups known. It appears, from our present knowledge, that the _Agarici_ have their geographic centre in the temperate zone, and especially in the colder portion of that zone. It is a curious circ.u.mstance that all the extra-European species of this genus _Agaricus_ may be referred to various European subgenera.

In tropical countries it appears that the _Agarici_ occupy only a secondary position in relation to other genera of fungi, such as _Polyporus_, _Lenzites_, etc. North America, on the other hand, is richer in species of _Agaricus_ than Europe; for whilst the majority of typical forms are common to both continents, America further possesses many species peculiar to itself. In the temperate zone, so close is the a.n.a.logy prevailing between the various countries in respect to the _Agaricini_, that from Sweden to Italy, and as well in England as North America, the same species are to be found. Of 500 _Agaricini_ met with in St. Petersburg, there are only two or three which have not been discovered in Sweden; and again, of fifty species known in Greenland, there is not one that is not common in Sweden. The same remarks hold good in reference to the _Agaricini_ of Siberia, Kamtschatka, the Ukraine, etc. The countries bordering upon the Mediterranean possess, however, several peculiar types; and Eastern and Western Europe present certain dissimilarities in their Agaric inhabitants. Several species, for example, of _Armillaria_ and _Tricholoma_, which have been found in Russia, have been met with in Sweden only in Upland, that is, in the most eastern province; all the species which belong to the so-called _abiegno-rupestres_ and _pineto-montanae_ regions of Sweden are wanting in England; and it is only in Scotland that the species of northern mountainous and pine-bearing regions are met with--a circ.u.mstance explicable from the similarity in physical features between Sweden and the northern portions of Great Britain.

The species of _Coprinus_ appear to find suitable habitats in every quarter of the globe.

The _Cortinariae_ predominate in the north; they abound in Northern lat.i.tudes, especially on wooded hills; but the plains offer also some peculiar species which flourish during the rainy days of August and September. In less cold countries they are more scarce or entirely absent. The species of the genus _Hygrophorus_ would at first seem to have a similar geographical distribution to those of the last group; but this is really not the case, for the same _Hygrophori_ are to be found in nearly every country of Europe, and even the hottest countries (and those under the equator) are not dest.i.tute of representatives of this wide-spread genus.

The _Lactarii_, which are so abundant in the forests of Europe and North America, appear to grow more and more scarce towards both the south and north. The same may be stated in regard to _Russula_.

The genus _Marasmius_ is dispersed throughout the globe, and everywhere presents numerous species. In inter-tropical countries they are still more abundant, and exhibit peculiarities in growth which probably might justify their collection into a distinct group.

The genera _Lentinus_ and _Lenzites_ are found in every region of the world; their princ.i.p.al centre, however, is in hot countries, where they attain a splendid development. On the contrary, towards the north they rapidly decrease in number.

The _Polypori_ const.i.tute a group which, unlike that of the Agarics, especially belongs to hot countries. The _Boleti_ const.i.tute the only exception to this rule, since they select the temperate and frigid zones for their special abode, and some of them at times find their way to the higher regions of the Alps. No one can describe the luxuriance of the torrid zone in _Polypori_ and _Trametes_, genera of _Hymenomycetes_, which flourish beneath the shade of the virgin forests, where perpetual moisture and heat promote their vegetation and give rise to an infinite variety of forms. But though the genus _Polyporus_, which rivals _Agaricus_ in the number of its species, inhabits, in preference, warm climates at large, it nevertheless exhibits species peculiar to each country. This arises from the circ.u.mstance that the _Polypori_, for the most part, live upon trees, and are dependent on this or that particular tree for a suitable habitat; and the tropical flora being prolific in trees of all kinds, a mult.i.tude of the most varied forms of these fungi is a necessary consequence. _Hexagona_, _Favolus_, and _Laschia_ are common in inter-tropical countries, but they are either entirely absent or extremely rare in temperate climes.

When the majority of the species of a genus are of a fleshy consistence, it may generally be concluded that that genus belongs to a Northern region, even if it should have some representatives in lands which enjoy more sunshine. Thus the _Hydna_ are the princ.i.p.al ornaments of Northern forests, where they attain so luxuriant a growth and beauty that every other country must yield the palm to Sweden in respect to them. In an allied genus, that of _Irpex_, the texture a.s.sumes a coriaceous consistence, and we find its species to be more especially inhabitants of warm climates.

Most of the genera of _Auricularini_ are cosmopolitan, and the same is true of some species of _Stereum_, of _Corticium_, etc., which are met with in countries of the most different geographical position. In tropical countries, these genera of fungi a.s.sume the most curious and luxuriant forms. The single and not considerable genus _Cyph.e.l.la_ appears to be pretty uniformly distributed over the globe. The _Clavariaei_ are equally universal in their diffusion, although more plentiful in the north; however, the genus _Pterula_ possesses several exotic forms, though in Europe it has but two representative species.

That beautiful genus of _Hymenomycetes_, _Spara.s.sis_, occupies a similar place next the _Clavariaei_, and is peculiarly a production of the temperate zone and of the coniferous region.

The fungi which const.i.tute the family of _Tremellini_ prevail in Europe, Asia, and North America, and exhibit no marked differences amongst themselves, notwithstanding the distances of the several countries apart. It must, however, be stated that the _Hirneolae_ for the most part inhabit the tropics.

We come now to the _Gasteromycetes_--an interesting family, which exhibits several ramifications or particular series of developments.

The most perfect _Gasteromycetes_ almost exclusively belong to the warmer division of the temperate, and to the tropical zone, where their vegetation is the most luxuriant. Of late the catalogue of these fungi has been greatly enriched by the addition of numerous genera and species, proper to hot countries, previously unknown. Not uncommonly, the exotic floras differ from ours, not merely in respect of the species, but also of the genera of _Gasteromycetes_. It must, besides, be observed that this family is rich in well-defined genera, though very poor in distinct specific forms. Among the genera found in Europe, many are cosmopolitan.

The _Phalloidei_ present themselves in the torrid zone under the most varied form and colouring, and comprise many genera rich in species.

In Europe their number is very restricted. As we advance northward they decrease rapidly, so that the central districts of Sweden possess only a single species, the _Phallus impudicus_, and even this solitary representative of the family is very scarce. In Scania, the most southern province of Sweden, there is likewise but one genus and one species belonging to it, viz., the _Mutinus caninus_. Among other members of the _Phalloidei_, may be further mentioned the _Lysurus_ of China, the _Aseroe_ of Van Diemen's Land, and the _Clathrus_, one species of which, _C. cancellatus_, has a very wide geographical range; for instance, it is found in the south of Europe, in Germany, and in America; it occurs also in the south of England and the Isle of Wight; whereas the other species of this genus have a very limited distribution.

The _Tuberacei_[D] are remarkable amongst the fungi in being all of them more or less hypogeous. They are natives of warm countries, and are distributed into numerous genera and species. The _Tuberacei_ const.i.tute in Northern lat.i.tudes a group of fungi very poor in specific forms. The few species of the _Hymenogastres_ belonging to Sweden, with the exception of _Hyperrhiza variegata_ and one example of the genus _Octaviana_, are confined to the southern provinces. The greater part of this group, like the _Lycoperdacei_, are met with in the temperate zone. Most examples of the genus _Lycoperdon_ are cosmopolitan.

The _Nidulariacei_ and the _Trichodermacei_ appear to be scattered over the globe in a uniform manner, although their species are not everywhere similar. The same statement applies to the _Myxogastres_, which are common in Lapland, and appear to have their central point of distribution in the countries within the temperate zone. At the same time, they are not wanting in tropical regions, notwithstanding that the intensity of heat, by drying up the mucilage which serves as the medium for the development of their spores, is opposed to their development.[E]

Of the _Coniomycetes_, the parasitic species, as the _Caeomacei_, the _Pucciniei_, and the _Ustilagines_, accompany their foster-plants into almost all regions where they are found; so that s.m.u.t, rust, and mildew are as common on wheat and barley in the Himalayas and in New Zealand as in Europe and America. _Ravenelia_ and _Cronartium_ only occur in the warmer parts of the temperate zone, whilst _Sartvellia_ is confined to Surinam. Species of _Podisoma_ and _Roestelia_ are as common in the United States as in Europe, and the latter appears also at the Cape and Ceylon. Wherever species of _Sphaeria_ occur there the _Sphaeronemei_ are found, but they do not appear, according to our present knowledge, to be so plentiful in tropical as in temperate countries. The _Torulacei_ and its allies are widely diffused, and probably occur to a considerable extent in tropical countries.

_Hyphomycetes_ are widely diffused; some species are peculiarly cosmopolitan, and all seem to be less influenced by climatic conditions than the more fleshy fungi. The _Sepedoniei_ are represented by at least one species wherever _Boletus_ is found. The _Mucedines_ occur everywhere in temperate and tropical regions, _Penicillium_ and _Aspergillus_ flourishing as much in the latter as in the former. _Botrytis_ and _Peronospora_ are almost as widely diffused and as destructive in warmer as in temperate countries, and although from difficulty in preservation the moulds are seldom represented to any extent in collections, yet indications of their presence constantly occur in connection with other forms, to such an extent as to warrant the conclusion that they are far from uncommon.

The _Dematiei_ are probably equally as widely diffused. Species of _Helminthosporium_, _Cladosporium_, and _Macrosporium_ seem to be as common in tropical as temperate climes. The distribution of these fungi is imperfectly known, except in Europe and North America, but their occurrence in Ceylon, Cuba, India, and Australasia indicated a cosmopolitan range. _Cladosporium herbarum_ would seem to occur everywhere. The _Stilbacei_ and _Isariacei_ are not less widely diffused, although as yet apparently limited in species. _Isaria_ occurs on insects in Brazil as in North America, and species of _Stilb.u.m_ and _Isaria_ are by no means rare in Ceylon.

The _Physomycetes_ have representatives in the tropics, species of _Mucor_ occurring in Cuba, Brazil, and the southern states of North America, with the same and allied genera in Ceylon. _Antennaria_ and _Pisomyxa_ seem to reach their highest development in hot countries.

The _Ascomycetes_ are represented everywhere, and although certain groups are more tropical than others, they are represented in all collections. The fleshy forms are most prolific in temperate countries, and only a few species of _Peziza_ affect the tropics, yet in elevated districts of hot countries, such as the Himalayas of India, _Peziza_, _Morch.e.l.la_, and _Geoglossum_ are found. Two or three species of _Morch.e.l.la_ are found in Kashmir, and at least one or two in Java, where they are used as food. The genus _Cyttaria_ is confined to the southern parts of South America and Tasmania. The United States equal if they do not exceed European states in the number of species of the _Discomycetes_. The _Phacidiacei_ are not confined to temperate regions, but are more rare elsewhere. _Cordierites_ and _Acroseyphus_ (?) are tropical genera, the former extending upwards far into the temperate zone, as _Hysterium_ and _Rhytisma_ descend into the tropics. Amongst the _Sphaeriacei_, _Xylaria_ and _Hypoxylon_ are well represented in the tropics, such species as _Xylaria hypoxylon_ and _Xylaria corniformis_ being widely diffused. In West Africa an American species of _Hypoxylon_ is amongst the very few specimens that have ever reached us from the Congo, whilst _H. concentric.u.m_ and _Ustulina vulgaris_ seem to be almost cosmopolitan. _Torrubia_ and _Nectria_ extend into the tropics, but are more plentiful in temperate and sub-tropical countries. _Dothidea_ is well represented in the tropics, whilst of the species of _Sphaeria_ proper, only the more prominent have probably been secured by collectors; hence the _Superficiales_ section is better represented than the _Obtectae_, and the tropical representatives of foliicolous species are but few.

_Asterina_, _Micropeltis_, and _Pemphidium_ are more sub-tropical than temperate forms. The _Perisporiacei_ are represented almost everywhere; although species of _Erysiphe_ are confined to temperate regions, the genus _Meliola_ occupies its place in warmer climes.

Finally, the _Tuberacei_, which are subterranean in their habits, are limited in distribution, being confined to the temperate zone, never extending far into the cold, and but poorly represented out of Europe.

One species of _Mylitta_ occurs in Australia, another in China, and another in the Neilgherries of India; the genus _Paurocotylis_ is found in New Zealand and Ceylon. It is said that a species of _Tuber_ is found in Himalayan regions, but in the United States, as well as in Northern Europe, the _Tuberacei_ are rare.

The imperfect condition of our information concerning very many countries, even of those partially explored, must render any estimate or comparison of the floras of those countries most fragmentary and imperfect. Recently, the mycology of our own islands has been more closely investigated, and the result of many years' application on the part of a few individuals has appeared in a record of some 2,809 species,[F] to which subsequent additions have been made, to an extent of probably not much less than 200 species,[G] which would bring the total to about 3,000 species. The result is that no material difference exists between our flora and that of Northern France, Belgium, and Scandinavia, except that in the latter there are a larger number of Hymenomycetal forms. The latest estimates of the flora of Scandinavia are contained in the works of the ill.u.s.trious Fries,[H]

but these are not sufficiently recent, except so far as regards the _Hymenomycetes_, for comparison of numbers with British species.

The flora of Belgium has its most recent exponent in the posthumous work of Jean Kickx; but the 1,370 species enumerated by him can hardly be supposed to represent the whole of the fungi of Belgium, for in such case it would be less than half the number found in the British Islands, although the majority of genera and species are the same.[I]

For the North of France no one could have furnished a more complete list, especially of the microscopic forms, than M. Desmazieres, but we are left to rely solely upon his papers in "Annales des Sc. Nat." and his published specimens, which, though by no means representative of the fleshy fungi, are doubtless tolerably exhaustive of the minute species. From what we know of French _Hymenomycetes_, their number and variety appear to be much below those of Great Britain.[J]

The mycologic flora of Switzerland has been very well investigated, although requiring revision. Less attention having been given to the minute forms, and more to the _Hymenomycetes_ than in France and Belgium, may in part account for the larger proportion of the latter in the Swiss flora.[K]

In Spain and Portugal scarce anything has been done; the small collection made by Welwitsch can in no way be supposed to represent the Peninsula.

The fungi of Italy[L] include some species peculiar to the Peninsula.

The _Tuberacei_ are well represented, and although the _Hymenomycetes_ do not equal in number those of Britain or Scandinavia, a good proportion is maintained.

Bavaria and Austria (including Hungary, and the Tyrol) are being more thoroughly investigated than hitherto, but the works of Schaeffer, Tratinnick, Corda, and Krombholz have made us acquainted with the general features of their mycology,[M] to which more recent lists and catalogues have contributed.[N] The publication of dried specimens has of late years greatly facilitated acquaintance with the fungi of different countries in Europe, and those issued by Baron Thumen from Austria do not differ materially from those of Northern Germany, although Dr. Rehm has made us acquainted with some new and interesting forms from Bavaria.[O]

Russia is to a large extent unknown, except in its northern borders.[P] Karsten has investigated the fungi of Finland,[Q] and added considerably to the number of _Discomycetes_, for which the climate seems to be favourable; but, as a whole, it may be concluded that Western and Northern Europe are much better explored than the Eastern and South-Eastern, to which we might add the South, if Italy be excepted.

We have only to add, for Europe, that different portions of the German empire have been well worked, from the period of Wallroth to the present.[R] Recently, the valley of the Rhine has been exhaustively examined by f.u.c.kel;[S] but both Germany and France suffered checks during the late war which made their mark on the records of science not so speedily to be effaced. Denmark, with its splendid Flora Danica still in progress, more than a century after its commencement,[T] has a mycologic flora very like to that of Scandinavia, which is as well known.

If we pa.s.s from Europe to North America, we find there a mycologic flora greatly resembling that of Europe, and although Canada and the extreme North is little known, some parts of the United States have been investigated. Schweinitz[U] first made known to any extent the riches of this country, especially Carolina, and in this state the late Dr. Curtis and H. W. Ravenel continued their labours. With the exception of Lea's collections in Cincinnati, Wright's in Texas, and some contributions from Ohio, Alabama, Ma.s.sachusetts, and New York, a great portion of this vast country is mycologically unknown. It is remarkably rich in fleshy fungi, not only in _Agaricini_, but also in _Discomycetes_, containing a large number of European forms, mostly European genera, with many species at present peculiar to itself.

Tropical forms extend upwards into the Southern States.

The islands of the West Indies have been more or less examined, but none so thoroughly as Cuba, at first by Ramon de la Sagra, and afterwards by Wright.[V] The three princ.i.p.al genera of _Hymenomycetes_ represented are _Agaricus_, _Marasmius_, and _Polyporus_, represented severally by 82, 51, and 120 species, amounting to more than half the entire number. Of the 490 species, about 57 per cent. are peculiar to the island; 13 per cent. are widely dispersed species; 12 per cent.

are common to the island and Central America, together with the warmer parts of South America and Mexico; 3 per cent. are common to it with the United States, especially the Southern; while 13 per cent. are European species, including, however, 13 which may be considered as cosmopolitan. Some common tropical species do not occur, and, on the whole, the general character seems sub-tropical rather than tropical.

Many of the species are decidedly those of temperate regions, or at least nearly allied. Perhaps the most interesting species are those which occur in the genera _Craterellus_ and _Laschia_, the latter genus, especially, yielding several new forms. The fact that the climate is, on the whole, more temperate than that of some other islands in the same lat.i.tudes, would lead us to expect the presence of a comparatively large number of European species, or those which are found in the more northern United States, or British North America, and may account for the fact that so small a proportion of species should be identical with those from neighbouring islands.

In Central America only a few small collections have been made, which indicate a sub-tropical region.