462 DISEASES OF CULTIVATED PLANTS 



air-cavity of the stoma; conidiophores septate, producing a 

 single hyaline conidium from each of the three or four upper 

 cells of the conidiophore. 



The conidiophores with their conidia exactly resemble the 

 basidia of the Hemibasidiosmycetes. 



Defoliation of larches (Meria caricis, Vuill. =Harti- 

 gidla lands, Syd. ; Allescheria laricis^ R. Hartig) is some- 

 times the cause of premature falling of the needles, which is 

 injurious to nursery stock. The fungus appears as minute 

 white specks of mould, issuing from the stomata on the under 

 surface of the leaves ; at a later stage it occurs on both sur- 

 faces. The affinities of the fungus are uncertain. The 

 terminal branchlets producing the conidia are 2-5-septate, and 

 each cell produces a single spore or conidium, which is 

 exactly the structure of the basidia in the Hemibasidiomycetes, 

 Auricularia^ etc. Lindau places the fungus in the Hypho- 

 mycetaceae. This position is considered as untenable by 

 Vuillemin, who points out that the conidiophores do not 

 spring directly from the vegetative mycelium, but from a 

 pseudoparenchymatous mass of tissue occupying the air 

 cavity below a stoma, which may represent the primordium of 

 some ascomycetous fungus, arrested in its development. 

 The conidia are hyaline, continuous, cylindrical, and slightly 

 narrowed at the centre. 



Hartig, Zentr. f. d. ges. Forstwesen, 1889. 



Lindau, Engl.-Prantl. Nat. Pflanzen., ' Pilze,' Nachtr. 1900, 



P- 558. 



Lindau, Rabenh. Kr.-FL, Erster Band, 8 Abteil., ' Pilze,' 



p. 260 (1905). 



Vuillemin, Ann. My col, 3, p. 340 (1905). 



NEGATOR (MASSEE) 



Spore-bed or sporodochium erumpent, small, slightly 

 convex, becoming orange-red; conidia oblong or elliptic, 

 catenulate, continuous, the chains breaking up, contents of 

 conidia orange coloured. 



A remarkable genus, without any near affinities. Probably 

 a phase of some higher form. 



Coffee-twig disease. This disease, caused by Necator 



