214 
NATURE 
[ FEBRUARY 17, 1923 

“Essai taxonomique ” (1900), and it therefore differs 
in many important features from that of Massee, which 
was based on the work of Fries. It is new to British 
mycologists, and will doubtless puzzle somewhat many 
of the older workers ; but it represents an important 
attempt to incorporate in a systematic treatise the 
anatomical and microscopical data which various 
investigators have brought to light during the last half- 
century. 
In the classification adopted by Fries, Berkeley, 
Massee, and others, the main divisions of the Agaricinez 
were based on spore-colour. We were thus at the out- 
set provided with Leucospore, Rhodospore, Ochro- 
spore, Porphyospore, and Melanospore ; but in the 
present volume these groups have disappeared and 
spore-colour has become a character of relatively minor 
importance. In Rea’s classification, the Agaricales are 
divided into (1) the Agaricinee, containing the bulk of 
the lamellate fungi in one sub-order Agaricacezé ; (2) the 
Cantharellinez ; and (3) the Boletinee, the last named 
including Paxillus and Boletus. The divisions of the 
Agaricacee are based first on the nature of the re- 
ceptacle, then on the presence or absence of a ring, etc. ; 
and it is only the final distinctions, separating the genera 
from one another, which for the most part are hased on 
spore-colour. No doubt this new classification has its 
advantages ; but some of its defects are sufficiently 
obvious. Thus, while Anellaria differs from Panzolus 
in little more than the possession of a membranous, 
often fugacious, ring, we find that Anellaria is placed 
close to Lepiota and Paneolus close to Collybia. For 
Fries, the genus Panzolus included the species sub- 
sequently placed by Karsten in Anellaria. The re- 
viewer cannot but feel with Fries that the species of 
Panzeolus and Anellaria are closely related to one another 
and that these genera should not be so widely separated. 
The writer is inclined to doubt whether spore-colour 
is only of such minor importance as is now supposed. 
There is every reason to believe that the genus Coprinus, 
with its parallel- or subparallel-sided gills and the ripen- 
ing and discharge of its spores from below upwards on 
each gill, followed by autodigestion of the gills from 
below upwards, is monophyletic. Now the spores in 
this genus are all black or blackish fuscous. In it there 
are no species with white spores or spores that are pink, 
purple, ochraceous, or ferruginous. Yet in the genus 
there are species with rings, e.g. Coprinus comatus, and 
without rings, e.g. C. picaceus ; species with fairly thick 
flesh, e.g. C. atramentarius, and species with mem- 
branous flesh, e.g. C. plicatilis ; species with dimorphic 
basidia and species with quadrimorphic basidia ; species 
with large and numerous cystidia and species without 
cystidia ; species which live exclusively on dung and 
species which live exclusively on wood, etc.; yet, while 
NO. 2781, VOL. 111] 


the genus Coprinus was evolving, the colour of its spores 
remained constant. It is evident that, in the genus 
Coprinus, spore-colour is a more fundamental character 
than ring-formation. If this is so with Coprinus, it 
may well be the same with other genera of Agaricinez. 
Rea’s system of classification, although in some of its 
details it does not satisfy the writer, has the advantage 
that it will stir up thought and thus make for further 
progress. 
“ British Basidiomycete ” is distinctly Mr. Rea’s 
own book ; and, in writing it, he has adopted as regards 
species a somewhat conservative and independent 
attitude. Thus he includes descriptions of certain 
species which are now known to be identical with others 
—e.g. Coprinus oblectus, which is undoubtedly identical 
with C. sterguilinus, and Coprinus radians, which is 
generally considered as identical with C. domesticus. 
His independence is further shown by the fact that in 
certain groups he has adopted his own views rather 
than those of his fellow-workers in this country. Thus, 
in treating of the Clavariz, he has not followed entirely 
the revision of the British Clavarie as given by Cotton ; 
while, in some instances, in treating of the Thelephorez, 
he has accepted American views rather than those of 
Miss Wakefield. 
The volume is indispensable to all students of fungi 
on both sides of the Atlantic ; for it is only by a clear 
understanding of the first-described European species 
that New World plants can be correctly named. The 
task of describing two thousand five hundred Basidio- 
mycete is no mean one; and botanists generally, as 
well as mycologists, are under a deep debt of gratitude 
to Rea, not merely for having accomplished it, but for 
having accomplished it so well, 
A. H. Recrnatp BuLrer. 

An Index to Periodical Literature. 
(1) The Subject Index to Periodicals. Issued by the 
Library Association. K: Science and Technology. 
Pp. 555. (London: Library Association, Stapley 
House, 1922.) 355. net. 
(2) Lhe Subject Index to Periodicals, 7920. Issued by 
the Library Association. A: Theology and Philo- 
sophy (including Folk-Lore). 
Library Association, Stapley House, 1922.) 6s. net. 
/E congratulate the Library Association on this 
welcome addition (r) to the valuable subject 
indexes to periodicals which it has already published. 
The present index contains the titles of 15,000 papers, 
published during the years 1917-19, obtained from the 
examination of goo periodicals. It would appear that 
more than half the papers indexed are in the English 
language, having been published in the British Empire 
Pp. 98. (London: - 
= 
é 
