3 6 Howard.—On a Disease of Tradescantia. 
Cladosporium is by no means unknown as a parasite, 
although its easy culture as a pronounced saprophyte suggests 
that special conditions either of the host or the Fungus are 
necessary before it can attack living plants with such energy 
as to cause an epidemic. 
Lopriore 1 has described an epidemic on Wheat caused by 
C. herbarum , and collected the literature to date. 
Frank 2 quotes yet other cases where various Monocoty¬ 
ledons, fruit trees, olives, tomatoes, cucumbers, &c., are 
injured by other species of Cladosporium , and also brings the 
literature up to date, showing at the same time what enormous 
confusion exists as to the connexion between this and other 
genera. 
The difficulties of confusion are increased when we find 
that Brefeld 3 describes as the conidial form of Microsphae- 
rella a Fungus of essentially the same type as that under 
discussion, and it is evident that nothing final can be done 
before we trace the more perfect stages. 
Brefeld refers to this type as the Ramularia form, and 
quotes Tulasne’s Fig. 7, Table XXXI, in the Carpologia , 
which certainly bears out his comparison. The doubt arises, 
however, whether Tulasne did not draw more than one Fungus 
in his figure. Tulasne 4 also refers this type to Pleospora. 
Hence it is evident that a long research will be necessary 
to clear up the numerous difficulties accumulated around the 
Fungus Cladosporium and its allies. 
In conclusion, I wish to thank Professor Marshall Ward, 
under whose constant supervision this work has been carried 
out, for much kind assistance and advice. 
Cambridge Botanical Laboratory, 
September 4, 1899. 
1 Die Schwarze des Getreides, Ber. d. deutsch. bot. Ges., 1892, Bd. x, p. 72. 
2 Die Krankheiten der Pflanzen, 2nd ed., 1896, p. 315, &c. 
3 Unters. aus dem ges. Gebiete, &c., Heft 8, p. 213, and Plate VI, Figs. 38-42. 
4 Carpologia, Vol. ii, Plate XXXII, Figs. 13 and 14. 
