LIST OF PLATES 



1. Representative fields from Hirst-trap slides illustrating diverse air 

 sporas. (Magnification: all x looo. At this magnification i sq. cm. of 

 field corresponds to 2-i cc. of air.) 



(a) Fine-weather air spora, Ascot, Berks., i2-oo hr., 27 June 1958. 

 Showing grass and nettle pollen, Cladosporiinn, Epicoccum, etc. 

 (/;) Damp-air spora, Ascot, Berks., 02-00 hr., 17 June 1958. Showing 

 spores of Ganoderma, Sporoholomyces, Tilletiopsis, and other hyaline 

 basidiospores. 



(c) Rain-t}'pe air-spora. Ascot, Berks., 04-30 hr., 13 June 1958. 

 Showing various ascospore t}'pes, Sporobolomyces, soot, etc. 



(d) Air-spora in a wheat crop at night during a thunder-storm, 

 Harpenden, Herts., 21-30 hr., 10 August 1959. Showing Puccinia 

 graminis uredospores, Cladosporinni, and unidentified ascospore. 



(e) Spores of Meniliiis lacrjmans from air of building with timber 

 affected by dry-rot. From camera lucida paintings by Maureen E. 

 Bunce ......... Frontispiece 



facing page 



2. Ehrenberg's illustration of sample of dust collected by Charles 

 Darwin on the Beagle near the Cape Verde Islands, January 1833 . 12 



3. Photographs by Worthington & Cole (1897) showing splash of a water 

 drop weighing 0-2 gm. (coated with lamp-black) falling 40 cm. into a 

 mixture of milk and water. ....... 36 



4. Rosebury-Henderson Capillary Impinger in operation, with air 

 entering first through a May & Druett Pre-impinger. (Inset shows 



the capillary in still conditions) ....... 96 



Appendix I. Typical components of the air-spora at a uniform magnifica- 

 tion. Mag. 1000 X . From camera lucida paintings by Maureen E. 

 Bunce ........... 207 



Plate 5. Phycomycetes, Ascomycetes, Fungi Imperfecti, Actinomy- 

 cetes 



Plate 6. Basidiomycetes, Lichens, Bryophytes, Pteridophytes, M\tco- 

 mycetes 



Plate 7. Pollens, and miscellaneous other objects 



Xlll 



