214 



ASCOMYCETES. 



active vegetation begins about two and a half months later than 

 in the plains, i.e. at the beginning of June. The season of 

 mature spores of Sphaerella is thus delayed till about the 

 middle of August. On 26 th September I found at this elevation 

 only a few spots on the larch needles, and 

 on these hardly any conidial cushions. By 

 28 th September this larch plantation was 

 already under snow." 



" It will thus be seen, that while at a 

 high elevation the larch can flourish with 

 a vegetative period extending only to three 

 and a quarter or four months, the Sphaerella 

 has not the time necessary for its develop- 

 ment, so that the larch, though much 

 handicapped, remains healthy. Similarly 

 with the larch in Siberia, it grows there, 

 as in the mountains, very slowly, yet this 

 parasite can no longer reach it." 



Sphaerella fragariae Tul. Strawberry 

 leaf- blight.-^ In summer free conidia 

 {Ramularia Tulasnei Sacc.) and pycnidia 

 are produced, while the perithecia ripen in spring. 



[This destructive disease of the strawberry has been recorded 

 from all parts of the United States. It first appears on the 

 upper surface as small reddish spots, which rapidly enlarge, 

 the centres withering and browning. The growth of the plants 

 and the crop-yield is seriously impaired.] (Edit.) 



Sph. gossypina Atks.^ [Cotton leaf-bhght is a disease on 

 leaves of the cotton plant caused by the Cerco^ora-stage of this 

 fungus. Small reddish spots appear on the leaf, enlarge, and 

 become dry whitish spots with a red margin. The comdia 

 are elongated and produced in long chains. The asci contain 

 eight elliptical spores, which are slightly constricted at the 

 septum when mature, one cell being usually somewhat smaller 

 than the other. This disease frequently accompanies that one 

 known as " yellow leaf-blight," or mosaic disease.] (Edit.) 



Fig. 105.— Enlarged asci. 



a, Immature asci without 

 paraphyses, as on April 30. 



b. Mature asci, from one of 

 which the spores are escap- 

 ing, as on June 1. x ^■^. 

 (Alter R. Hartig.) 



^Trelease, Winco^isin Exper. Station, 1885. 

 Scribner, F. L., Report U.S. Dtpt. of Agricviture, 1887. 

 papers by Arthur, Dudley, and Garman. 



^ Atkinson, Bulletin Torrey Botan. Club, Vol. xvm., 1891. 



Plate. Other 



