198 DISEASES OF CULTIVATED PLANTS 



Cladosporium herbarum to be the conidial condition of 

 Sphaerella Tulasnei. Lopriore has shown that diseased 

 grains as a rule do not germinate, but those that do grow 

 produce diseased plants, which clearly show the mycelium 

 of Cladosporium, under the form of long, reddish-brown 

 specks, even in the first leaf-sheath. 



Ascigerous condition. Perithecia subglobose, minute, asci 

 cylindric-fusoid, 8-spored ; paraphyses absent ; spores hyaline, 

 oblong, ends rather pointed, i-septate, the uppermost cell in 

 the ascus is usually slightly larger than the remainder, and 

 measures 28 x 6*5 fj.. 



Cladosporium form. Tufts dense, forming a velvety, 

 blackish, olive, effused patch, conidiophores erect, septate, 

 rarely branched, often nodulose or kneed. Conidia often 

 forming chains of 2-3, subcylindrical, pale olive, 1-3-septate 



10-35X4-7/*- 



Hcrmodcndron form. Stem erect, simple, bearing at apex, 



or laterally, a tuft of small, elliptical, continuous brown 

 conidia borne in simple or branched chains. This form is 

 often produced from broken ends of Cladosporium conidio- 

 phores when placed in a hanging drop. 



Janczewski, Extr. Bull. Acad. Set. Cracow, 1892-93-94. 

 Lopriore, Soudcr. aus Landwirth. Jahrb., 23 (1894). 

 Massee, AYrc' Bull., 1898, p. 321. 

 Prillieux, Malad. des Plantes Agric., 2. p. 252 (1807). 



A difficult disease to combat, as the Cladosporium con- 

 dition is one of our commonest of saprophytic fungi,^ 

 growing everywhere on dead and decaying vegetable matter* 

 As it is known that infected grain perpetuates the disease, it 

 is important that untainted seed only should be sown. 



Mulberry leaf rust. The haves of mulberries arc 

 frequently destroyed to a serious extent by Sphaerella 

 morifolia (Passer).' The leaves are infected in spring by the 

 conidial form of the fungus, one known as Cxlindrosporium 

 ;;wr/(Berlese)and.SV/A^Av//w mori ( HriosiandCav.). Diseased 

 leaves show a number of irregularly shaped blotches, pale 

 brown in colour with a darker edge. The fruit of the 

 fungus appears in irregular circles of small brown dots 

 on the patches, mostly on the upper surface of the leaf. The 

 spores of this form are quickly diffused and infect other 

 leaves ; this continues throughout the growing season. Injured 



