Proceedings 21 
WaNTED: FIELD WORKERS. 
_ Whilst investigating lately a certain group of fungi, I 
have been much struck by the fact that there exists a cer- 
tain kind of botanical work which is especially suitable for 
the members of a country Natural History Society to 
undertake. 
If a botanist is working at the anatomy of plants, or at 
physiological problems, then he requires the delicate scien- 
tific instruments and accessories only to be found in labor- 
atories; if he is engaged in systematic work, then, in order 
to monograph any group of plants he requires to work at 
the national herbaria, where access is to be had to types, 
7.e. the actual specimens from which the original descrip- 
tions were drawn. 
But there exists, further, a kind of botanical work—of 
great scientific value—which, so to speak, must be per- 
formed in the laboratory of Nature. Zhis ts Field Work. 
In the group of fungi which I have been studying, there 
is need of Field work being done to solve three problems 
connected with their life history. 
In order to understand the nature of these problems, I 
must briefly describe the characteristics of these fungi. 
The group is known as the Z£rysiphacee@, or White Pow- 
_ dery Mildews. They are parasitic fungi, attacking a great 
number of common flowering plants, on the surface of the 
stems or leaves of which they form white cobwebby patches. 
They are extremely common, and are superficially, at least, 
_ known to most people. They cause considerable damage 
- to many cultivated plants ; e.g. there is the Rose Mildew, 
_ which covers with white powder the leaves of wild and 
cultivated roses ; the Hop Mildew, to guard against which 
_ farmers sulphur their hops every year ; the Vine Mildew, 
_ prevalent in all the vineyards of Europe and America. 
There is also the Gooseberry Mildew, the Strawberry Mil- 
_ dew, the Pea and Bean Mildew, the Corn and Grass Mil- 
_ dew, the Apple, Pear and Cherry Mildew, &c. 
To anyone walking in the country, the white patches 
caused by the E£rysiphacee must have been frequently 
