86 
NOTES ON HYMENOMYCETES. 
measurements are not given with the diagnosis) are propounded as 
types, and also that the individuals giving measurements from such 
types are reliable, and capable of giving accurate measurements of 
such minute bodies. It is one thing to be able to see an object of 
2 or 3 p in diameter under the microscope, but quite another thing 
to measure the dimensions accurately. As an example of the truth 
of this anyone can refer for himself to authorities for the dimensions 
of the spores in three or four of the best known species, and com- 
pare the dimensions given by different authorities from their own 
determinations. The result will be that there will be found to be no 
absolute agreement between any two persons, except where one has 
copied (apparently) from the other. Take the following instances 
for what they are worth : — 
Coprinus comatus , Fries. 
11- 13 x 6-8 p. Karsten. 
12- 14 x 6-8 p. Britzelmayr. 
10-13 X 6-8 p. Bizzozero. 
18x11 p. W. G. Smith. 
14 x 8 p. Cooke Illus. t. 658. 
15 x 9 p. G. Massee in Herb. Kew. 
Coprinus atramentarius, Fries. 
6-10 x 4-6 p. Britzelmayr. 
9 x 6 /x. Cooke Illus. t. 662. 
9-10 x 6 p. Bizzozero. 
9- it) x 6 p. Karsten. 
12 x 6 p. G. Massee in Herb. Kew. 
9- 10 x 6 p. Saccardo. 
Coprinus jimetarius , Fries. 
15-18 x 9-12 p. Karsten. 
15-18 x 9-12 p. Bizzozero. 
10- 12 x 6-8 p. Britzelmayr. 
12 x 10 p. G. Massee in Herb. Kew. 
Coprinus plicatilis , Curtis. 
8-11 X 5-9 p. Saccardo. 
8-10 x 5-8 p. Britzelmayr. 
14 x 10 p. G. Massee in Herb. Kew. 
From these, and similar examples which might be added indefi- 
nitely, it is clear that the spores are exceedingly variable in size in 
the same species, and therefore of no value in the determination of 
species ; or else, not being themselves variable, that the sizes given 
indicate inaccurate measurement on the part of all observers but 
one, it follows that, until it is determined which is the accurate 
authority, spore dimensions are equally useless, and not only use- 
less but misguiding. Before there is any justification for the 
recognition of spore measurement as part of the diagnosis of a 
species, some better method for obtaining accuracy must be devised, 
it being perfectly clear that the present haphazard system is a dis- 
credited failure. 
