Farlow, W. G. (William Gilson)

A consideration ot the species
plantarum of Linnaeus as a "basis
for the starting point of the
nomenclature of cryptogams

NEW YORK BOTANtOA*’
fiAROEN, LIBRARY, ^

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A CONSIDERATION OF THE SPECIES PLANTARUM OF
LINNAEUS AS A BASIS FOR THE STARTING
POINT OF THE NOMENCLATURE
OF CRYPTOGAMS.

W. G. FARLOW.

[Privately Printed.]

THE LuESTHER T. KERTZ LIBRARY'
THE NEW YORK BOTANICAL GARDEN

THE LuES 'i 'HER T. iV^EFErZ LiBRARY
THE NEW YORK BOTANICAL GARDEN

A CONSIDERATION OF THE SPECIES PLANTARUM OF
LINNAEUS AS A BASIS FOR THE STARTING
POINT OF THE NOMENCLATURE
OF CRYPTOGAMS.

W. G. FARLOW.

[Privately Printed.]

UK

5r7

e.2-

A CONSIDERATION OF THE SPECIES PLANTARUM OF
LINNAEUS AS A BASIS FOR THE STARTING
POINT OF THE NOMENCLATURE OF
CRYPTOGAMS.

W. G. FARLOW.

At the Congress held in Vienna in 1905 it was voted to adopt Lin-
naeus’ Species Plantarum, 1753, as the starting point of the nomen-
clature of flowering plants and the question of the starting point for
that of cryptogams was referred to the Congress to be held at Brussels
in May, 1910. The adoption of the Species Plantarum was endorsed
practically by so large a proportion of phaenogamic botanists that its
acceptance came as near being universal as could ever be expected in
such a case. It may be assumed therefore that the Species Plantarum
is well adapted to serve as a basis for the nomenclature of phaenogams.
Were it true that it is as well, or nearly as well, adapted to serve as a
basis for the nomenclature of cryptogams, there would be no hesitation
on the part of cryptogamists in adopting it also. If it is not, there is
no reason why they should feel under any obligation, for the sake of a
merely formal uniformity in nomenclature, to follow in the steps of
other botanists.

In the first place we may ask why it is that the Species Plantarum
should be considered to be well adapted to the requirements of phaeno-
gamic botanists. The fact that it was the first work in which the
binomial nomenclature was methodically applied is a sufficient reason
why no work issued prior to 1753 should have been adopted as a basis
of nomenclature but that fact alone is not a sufficient reason for the
adoption of the Species Plantarum itself. An examination of that
work shows also other merits which should recommend it. It is an
admirable summary by the leading systematist of his day of several
hundred genera and some thousands of species found not only in
Europe but also in North America and other more remote parts of the
world. In fact on glancing over its pages one is surprised at the large
field covered by Linnaeus and the large number of exotic species which
are included in the work. In the numerous editions of the Species
issued at intervals of a few years until as late as 1830, some under the

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title of Systema Vegetabilium and Systema Plantarum, the Linnaean
traditions were handed down with additions and annotations by well
known botanists, so that there is no gap separating the original edition
from the date of the appearance of the first volume of De Candolle^ s
Prodromus in 1824. It should also be borne in mind that under the
careful guardianship of the Linnaean Society of London, the Linnaean
herbarium is still in existence and accessible to botanists. It is there-
fore not difficult to see that for a basis of nomenclature of flowering
plants the Species Plantarum was well chosen.

If we turn now to the Cryptogams of the Species we find a very
different state of things. To those who have not examined the Species
with reference to this point it might seem that the cryptogamists for
the sake of uniformity might be willing to make some sacrifice. For
such persons a comparative examination of the phaenogams and
cryptogams in the Species may be of interest. For this purpose I
have prepared a table showing the number of genera and species in the
two groups. The number of genera can be determined without
difficulty. The counting of the species is less easy since in some cases
it is not quite certain whether under a given name Linnaeus intended
to indicate a species properly speaking or merely a form or variety.
In my enumeration I have included only those forms clearly desig-
nated as species, omitting subspecific forms. That the enumeration
here given is conservative is shown by the fact that, while according to
the Codex Linnaeanus the total number of species in the Species
Plantarum is 5938, the total of my list is 5247, divided as follows.

Genera

Species

Phaenogams

1049

4630

Cryptogams

50

617

Total

1099

5247

Of the 50 genera and 617 species, 16 genera and 189 species are
Filices and there are in addition 24 species of the genus Lycopodium
which was placed by Linnaeus in Musci. Among the Filices are to be
found numerous characteristic species of America and the tropics and
in this respect the treatment of the group by Linnaeus is quite com-
parable with his treatment of phaenogams. For nomenclatorial
purposes the Filices and Lycopodium are even at the present day

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treated in the same manner as phaenogams, and it is a well known fact
that it is the custom to unite the vascular cryptogams and the phaeno-
gams in floristic works. So far as we are now concerned the higher
cryptogams need not enter into the discussion, but from the nomencla-
torial standpoint must be classed with phaenogams and there is there-
fore left 404 species and 33 genera for all the Bryophytes and Thallo-
phytes described in the Species Plantarum. But even in this small
number is included the genus Spongia under Algae with 11 species of
which at least the greater part are not even plants in any sense. Fur-
thermore, among the Bryophytes and Thallophytes there are almost
no extra-European species and of the European species a great pro-
portion are Northern. In short, although as far as phaenogams are
concerned the Species Plantarum includes characteristic representa-
tives of different parts of the world, as far as the Bryophytes and
Thallophytes are concerned it represents only a limited European flora.

The question may perhaps be asked by those who have not studied
specially any group of non- vascular cryptogams ; Although the number
of non-vascular cryptogams in the Species Plantarum is very much
smaller than that of Phaenogams, is it not perhaps the case that the
ratio represents approximately the relative size of the two groups in
nature? It has been the custom to state that the phaenogams out-
number the cryptogams, some even saying that they are much more
numerous. Such statements are based solely on an enumeration of
described species and fail to give information as to the probable actual
number of species. It is not possible to give figures on the subject
which are up to date and the statistics of even a few years ago are of
slight value for it is only within a few years that the study of crypto-
gams has been pursued in other parts of the world than Europe or, to
a less extent. North America. We can probably obtain a more
correct opinion if we consider probabilities. The number of known
species of Musci and Hepaticae has been very much increased in the
last few years and although the bryological flora of Europe and North
America is now so well known that no very large number of new species
is to be expected there, in other parts of the world and especially in
the tropics, it is evident that the work of exploration conducted by
trained specialists will bring to light a very large number of new spe-
cies. The same is true of lichens. In algae a very great increase of

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species is less to be expected partly for the reason that the region of
growth of marine algae, pelagic species excepted, is more limited than
that of land plants. But even in algae, it is probable that the known
species will be considerably increased.

The fungi offer a better field for comparison than other groups.
It is certainly true that the number of described species is decidedly
smaller than that of phaenogams. Are we then to conclude that there
are fewer fungi in the world than there are phaenogams? By no
means, for there is a possible inference which may be drawn from a
knowledge of the distribution of fungi to which, it seems to me, great
weight should be given. Year by year the number of known parasitic
fungi goes on increasing and, although we cannot assume that probably
every phaenogam has its parasite, the proportion which have is con-
stantly increasing. We also know that some species have not only one
but many parasites and, as a rule, the species which from their economic
value have been most carefully studied are the hosts of many fungi.
As an instance I may mention the species of the genus Vitis on which
several hundred species of fungi are known to grow, some to be sure
found also on other plants, but a large number peculiar to this
genus. When all genera have been studied as carefully as Vitis, we
shall undoubtedly find that the number of parasitic fungi in existence
is enormous. If to the parasitic we add the thousands of saprophytic
fungi, it may well be asked whether eventually it will not prove to be
true that the number of species of fungi is as great as that of phaeno-
gams. It seems to me that it should be plain to every one that if in the
Species Plantarum the proportion of phaenogams to cryptogams is
about ten to one, we must admit that although the work is sufficiently
comprehensive to serve as a basis for the nomenclature of the former,
it is entirely inadequate in the case of the latter.

I have referred to the restricted range of the species of cryptogams
described by Linnaeus and to their small number. If we go farther
and examine the character of the descriptions themselves we find that
they are in many cases vague and unintelligible, which is nothing more
than might have been expected in that day before the scientific study
of the group had really begun. The algae in particular are from the
modern point of view a strange medley. The genera Jungermannia,
Targionia, Marchantia, Blasia, Riccia and Anthoceros I have in my

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enumeration included in Bryophytes where they properly belong,
although they were placed by Linnaeus in algae as well as the genus
Lichen with 80 species. The genus Tremella * with 7 species was also
included in algae although as far as the scant descriptions can be
identified, 3 are species of fungi, 3 algae and one a lichen. Some of
the 12 species of Byssus are algae but the majority it is impossible to
recognize. Of the 11 species of Spongia nearly all are animals.

Of the later editions of the Species Plantarum the fourth, according
to some the fifth, has a partial revision of the fungi by Link and of the
mosses by Schwaegrichen, but as these parts were not published until
1824-30 and do not follow in any way the original edition of Linnaeus,
so far as priority of nomenclature is concerned, they need not be
considered here. Of the Systema Plantarum, Reichard 1780 and the
Systema Vegetabilium by Gmelin, 1796, by Persoon 1797 and Sprengel
1827, it can be said that although they include more species than the
original edition of Linnaeus they are open to the same objections and,
as will be seen later, the dates of their publication are so near those of
far better works that their nomenclatorial value is of trivial importance.
If I have dwelt at what may seem too great length on a consideration
of the value of the Species Plantarum as a basis of nomenclature it has
been for the purpose of trying to make clear to those to whom uni-
formity in nomenclature seems to be of the first importance, why it is
that to expect cryptogamists to adopt the Species on the same basis as
do phaenoganiists is unreasonable. To the latter the Species repre-
sents a fundamental treatise; to the former a very meagre and unsatis-
factory list of plants belonging to groups of which, in the time of
Linnaeus, there was really no exact knowledge.

One would be glad to adopt as a basis of nomenclature some one
work which bears the same relation to cryptogams as does the Species
Plantarum to phaenogams, but there has never been any such work and
there never will be for a very good reason. The phaenogams form a
homogeneous group. The cryptogams do not, but consist of a num-
ber of different groups and the fundamental works relating to them
appeared at different dates, all, however, considerably later than 1753.
The specialists who study Bryophytes, Lichens, Algae and Fungi are
entirely justified in adopting different works as a basis of nomenclature.

* See note at end of this paper.

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The question they should ask is: what was the first work on Bryo-
phytes, on Lichens, on Algae, on Fungi, in which those groups were
scientifically and comprehensively treated.

It is not possible to enter at this time on a general consideration of
this point. Although that part of Linnaeus’ Species which related to
Bryophytes appears to have greater value than that which relates to
Thallophytes, since for one reason his citations of Dillenius’ figures
help one to understand to what plants the brief descriptions were
applied, it must certainly be admitted that Hedwig’s Species Mus-
corum, of which the first volume appeared in 1801, is the fundamental
work on mosses and that Hedwig with whom the scientific study of
mosses begun may be called the Linnaeus of Bryology. Acharius
stands in the same relation to lichenology and it is a question to be
settled by lichenologists whether the Lichenographia Universalis of
1810 or the earlier Methodus is to be given the preference. For
algae, the. Systema Algarum of C. A. Agardh has been suggested.
It is, however, out of the question to refer more in detail to the groups
just mentioned but it will be sufficient if we consider the case of fungi
somewhat more minutely although the subject is perplexing and
complicated even to those more particularly interested in this group
and probably to others wearisome.

In the Species Plantarum 1073 pages are given to phaenogams;
15 pages only are given to fungi, including Agaricus 27 species. Boletus
I2> Hydnum 4, Phallus 2, Clathrus 3, Elvela 2, Peziza 8, Clavaria 8,
Lycoperdon 9, and Mucor 11. To these must be added 3 of the
species of Tremella placed by Linnaeus in algae, making 89 fungi in
all. Of these not one is extra-European and only 8 are cited as grow-
ing in Italy or Southern Europe. To consider that a work of such a
limited scope should serve as a basis of nomenclature of a group whose
species are numbered by thousands seems to me preposterous. All
that we can say of the fungi in the Species Plantarum is that they show
plainly that in 1753 next to nothing was known of that large group and
one may be pardoned for saying that in what Linnaeus wrote about
fungi he was not a Linnaeus. We must search elsewhere for a funda-
mental work on the subject. In the later editions of the Species and
the Systema Vegetabilium, as I have said, the treatment of fungi is

not in any way satisfactory, and it was not until about fifty years after
the publication of the Species that there appeared anything which
could be called a general and comprehensive work on the species of
fungi. If mycologists were asked who exerted the greatest influence
in placing systematic mycology on a firm basis they would say Elias
Fries and the Systema Mycologicum, of which the first volume ap-
peared in 1821, had an influence in shaping the study as no other work
had had. In saying this I do not wish in any way to underrate the
value of the Synopsis Methodica Fungorum of Persoon, issued in 1801,
but of the two I think that the Systema is the one which has had de-
cidedly the greater influence in shaping the progress of descriptive
mycology. In its three volumes together with the two volumes of the
Elenchus which is a part of the Systema, we find for the first time an
account of the Mycological flora of a considerable portion of the world
rather than an account of certain orders of fungi mainly of Europe.
In the Epicrisis of 1836-38, the Summa Vegetabilium Scandinaviae
1849, and the Hymenomycetes Europaei 1874, we have important
revisions and commentaries by Fries of his earlier work. The leones
Selectae Hymenomycetum include 200 plates executed under his
supervision of species which cannot well be studied by dried specimens
alone. The herbarium of Fries is still at Upsala and the Sclero-
myceti Sueciae, a collection of 450 small parasitic species, is to be
found in herbaria in Europe and this country and has been the subject
of critical commentaries by several botanists. The fact that the
volumes of the Systema did not appear in the same year does not ap-
pear to me to present a serious practical difficulty, as Volume I con-
taining Hymenomycetes appeared in 1821 and Volume II with Disco-
mycetes and Pyrenomycetes in 1822-23. Volume III, which did not
appear until ten years later, includes Gasteromycetes and Fungi
Imperfecti.

The Synopsis of Persoon, although to be preferred to any previous
work, is considerably less extensive in the number and range of the
species given than the Systema, the number being about two and a
half times as great and, in general, the Systema presents a decidedly
more modern way of treating the group. A fuller consideration of the
comparative merits of the Systema and the Synopis is out of the
question in this place as it would require more time than can be

8

allowed and because the details are such that they could not readily be
followed except by mycologists who have studied the question minutely.
I have no right to encroach further on your patience and need only, in
conclusion, repeat that the Species Plantarum is quite unfit to serve as a
basis for the nomenclature of fungi, and that the Systema of Fries seems
to me to be better adapted for the purpose than any other work. In
any case to go back earlier than the Synopsis of Persoon would only
tend to perpetuate the present uncertainty and confusion and would
open the door to those who, regarding nomenclature as an end in itself
and not merely a means by which the necessary evil of naming plants
can be reduced to a minimum, devote time and labor to the undesir-
able task of unearthing names which are at the best uncertain, at the
sacrifice of names which have been in universal use for many years,
and whose meaning is perfectly clear. To my mind the object should
be, not to attempt to seek perfection in authority and priority — a
hopeless task — but rather to select the best solid basis in some com-
prehensive work. Even then, there is the question of genera con-
servanda^ and I believe that, whatever work or date is adopted, it will
be most desirable to adopt a list of genera conservanda. There is
nothing illogieal in this and practically there are great advantages
unless one believes in the theory that mere changing of names is a
merit in science. That theory I certainly do not accept, but hold that
the fewer changes of names the better.

It has been my misfortune never to have found anything perfect.
Some of my friends have perfect systems of classifications of books,
of herbaria or of plants. In trying to apply perfect methods I always
recall a visit in company with Sir Joseph Hooker to an establishment
not a thousand miles from here. The person in charge said, ^^we
think we have a perfect museum-case which we would like to show you.^^
^^Yes’’ said Sir Joseph, am always glad to see what I have never
seen. But what do you keep in the case?’^ A key was produced,
but by no amount of coaxing and forcing could the case be opened.

* From a paper by Austin H. Clark in Science of Jan. 28, 1910, entitled The strict
Application of the Law of Priority to Generic Names, we are apparently warranted in
believing that the principle of adopting genera conservanda is approved by a large
number of zoologists.

^'Yes” said Hooker, 'H presume that it is perfect but I prefer cases
which open/^ The same remark would apply to a good many systems.
They are perfect until we try to find out what is in them .

Note. The genus Tremella affords a good illustration of the advantage in
adopting Fries’ Systema as a basis for the classification of fungi and avoiding
the futile attempt by searching through the complicated and obscure writings
which appeared between 1753 and the early part of the 19th century to replace
names in general use at the present day by names in regard to which it is al-
most impossible to say what was meant by the authors. Tremella has for
many years been treated as a genus of fungi and the greater part of the species
of the genus given in Fries’ Systema are still recognized as valid species while
those which have since been separated generically are still regarded as closely
related to Tremella. The attempt to revive the Tremella of Linnaeus has
resulted only in adding a number of superfluous synonyms to mycological
literature without affecting the stability of the genus as it has been interpreted
by mycologists for nearly a hundred years.

In the discussion following the reading of the present paper at the meeting
of the Botanical Society of America at Boston, Dec. 29, 1909, one of the
speakers stated that he was inclined to regard Tremella L. as belonging to
algae and it was later remarked that it might be well to abandon the name
Tremella as a genus of fungi. This opinion appeared to be based on the fact
that T. Nostoc L. is an alga but there is no reason for believing that Linnaeus
regarded T. Nostoc rather than any other of his seven species as the type of
the genus. In the case of older writers we have no means of knowing what
species they regarded as types, and even if we accept the opinion of some bot-
anists that the first species named should be regarded as the type, a view
entirely arbitrary and unwarranted it seems to me, Tremella could not be
placed in algae since the first species named was T. juniperina, a fungus
belonging to the genus Gymnosporangium. As Tremella has entirely dis-
appeared from algological literature and is still recognized as the type genus of
the Tremellinaceae of fungi what possible good could be accomplished by over-
turning names generally accepted and replacing them by names at the best
very doubtful.

Attempts to revive Tremella L. as a genus of fungi have not been fortunate.
Prof. Arthur as a conscientious advocate of the view that the first named
'species should be regarded as the type, in his paper on Generic Nomen-

10

clature of the Cedar Apples'’ in 1901 transferred the known species of Gym-
nosporangium to Tremella. Had his view been accepted it would have neces-
sitated giving other names to the species of Tremella as now recognized. But
only two years previously, in 1889, Prof. Arthur in his paper, ^'Indiana Plant
Rusts listed in Accordance with the Latest Nomenclature” had reached the
conclusion that the name Puccinia must be abandoned for the large genus of
rusts to which it was usually applied and transferred to the species of Gym-
nosporangium and again in his recent writings he returns to Gymnosporangium
as a valid genus. Evidently, even when made by those whose ability and
conscientious aim are beyond question the search for older names in the con-
fusing literature following 1753 and previous to Fries has not resulted in that
permanence of nomenclature which it was hoped would be attained. It would
have been far better to have retained Tremella in the Friesian sense as is done
by most modern mycologists and to have accepted Gymnosporangium as it
has long been understood by mycologists and thus have avoided adding to the
large number of synonyms names which have quickly disappeared except as
curiosities of botanical literature. By adopting a work like Fries’ Systema
as the basis of nomenclature the dreary and unnecessary labor of trying
to account for all the vague names given by older writers and the perpetual
changing of names long in use and well understood in consequence of what
are often no more than conjectures as to what the older species were would
be avoided.

h.:-

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