249 



Dothiora. 



The spherical apothecia are embedded in the substratum, which 

 they rupture into lobes, while they themselves dehisce by 

 irregular fissures. The club-shaped asci contain eight colourless 

 or yellow, club-shaped or spindle-shaped, multicellular spores. 

 Paraphyses are never present. 



Dothiora sphaeroides (Pers.) is regarded by Eostrup as the 

 cause of a disease of the Lombardy poplar (Pojndi/s 2)i/ramidalu), 

 in which the branches, particularly those of the upper part 

 of the tree, die one after another till all are gone. The spores 

 are club-shaped and constricted at the middle ; each half is 

 divided by four or five cross-septa, and each cell so formed 

 is again subdivided by a longitudinal septum. 



Vuillemin ascribes the same disease to Didyviosphacria 

 pojndina Yuill. (see p. 218). 



According to Eehm, Du. spliacroidcs also occurs on Popidus 

 tremida, and is distinguishable from Do. imUila (Fr.) on both 

 Populvs italica and P. trcmnUi. 



Heterosphaeria. 



The spherical apothecia are at first embedded, but later emerge 

 through the covering layers and dehisce, their apices breaking 

 up into teeth-like lobes : they are dark-brown or black in colour. 

 The asci are club-shaped and contain eight spores, which are 

 colourless, oblong or club-shaped, and consist of one, two, or 

 four cells. Iodine colours the pores of the asci blue. Tlie 

 paraphyses are colourless and thread-like. 



Heterosphaeria Patella (Tode). (Britain and U.S. America.) 

 The asci contain eight bicellular spores. The paraphyses are 

 thread-like and septate, some being forked or branched ; they 

 bear scalpel-shaped conidia. 



The mature apothecia are found chiefly on the stems of 

 various UmbcUifcrac, e.g. Dcmcus Carota, Anethum graveolens, 

 Petroselinum, sativum, Pastinaca, etc. A variety alpestris occurs 

 amongst the mountains on Heraclcum Sp)hondylmm, also on 

 Gentiana lutea, Vcratrum viride, etc. liehm and others believe 

 that the fungus attacks living green parts of plants, and reaches 

 maturity in the following year on the killed organs. 



