Epidemic Plant Diseases. F. T. Brooks. 239 



enormous. Probably many millions of pomids are lost even* 

 \-ear by the attacks of parasitic fungi upon food plants. It is 

 b^- no means unkno\Mi for a disease of epidemic character to 

 wipe out the cultivation of a certain product in an entire countr\", 

 but the toll le\-ied is usually of a more insidious kind. For in- 

 stance, even in the best \vheat-gro%ving countries, the losses of 

 crop due to attacks of rust fungi are computed to be rarely less 

 than 10 per cent., and are often more, while in certain parts of 

 Canada, Austraha and Africa, the loss of crop from this cause 

 may be neariy complete. With wound parasites, the losses may 

 be equally serious if the diseases caused by them are neglected. 



NOTE. 



FLORA OF A BLACKBIRD S NEST IN AUGUST. 



A very young \isitor brought in to me the other day a 

 blackbird's nest of this year's building and opportunity was 

 taken to examine the material. Quite a number of P\Tenomy- 

 cetes were foimd to be in fruit. Other famOies were conspicuous 

 by their absence. The short hst is perhaps of some interest as 

 sho\\"ing what species were in fruiting condition on August 15th, 

 1923, after a very dry summer. It should be stated to the credit 

 of the blackbird as a collector that several of the species had 

 not been noted in the locahty before. 

 Mycosphaerella macidiformis (Pers.) Schroet. on leaves. 

 Leptosphaeria microsccypica Karst. on grass leaf. 

 Leptosphaeria Doliolum (Pers.) Ces. and de Not. 

 Leptosphaeria rubicunda Rehm on herbaceous stem. Spores 

 27-30 X 2-5-3 /i. Grove [Joiirn. of Bot. 1912, p. 49) says 

 20 X 2-5 /x, on Conitun. I have a specimen on an umbeUifer- 

 ous stem from Gloucestershire with spores — 25-40 x 3-5-4-5 /x, 

 second cell from above swollen. Winter says 45 ■. 2-5-3 /z. 

 Probably all one species. 

 Leptosphaeria derasa (B. and Br.) Auersw. on Scnecio Jacohaea. 

 Pleospora herbarum (Pers.) Rabh. 

 Pleospora infectoria Fuck, on grass stem. 

 Ophioholiis tenelliis (Auersw.) Sacc. on stem of Galium sp. 

 Gnomonia inclinata (Desmaz.) Auersw. on horse-chestnut leaf. 

 Gnomonia cerastis (Riess) Ces. and de Not. on Acer campestre 



peduncle. 

 Rhytisma aceriniim (Pers.) Fr. 



