200 FUNGOID PESTS OF CULTIVATED PLANTS. 



MAPLE-LEAF PHLCEOSPORE. 

 Phleospora Aceris (Lib.), PI. XIX. fig. 2 



This parasite is found commonly on living leaves of Acer campestre 

 and other species. It occurs upon small spots on the under surface of 

 the leaves, and the pustules are destitute of any proper conceptacle, but 

 are produced beneath the cuticle in special cavities or cells, and are of a 

 brown colour. The conidia are long and straight (22-28 x 5 ju), very 

 distinctly divided by three transverse septa, extruded, when mature, from 

 the orifice of the pustule in small pallid tendrils. 



This was called Septoria Aceris by Berkeley when the genus Septoria 

 was imperfectly defined. Whilst the trees still remain shrubby it may be 

 possible to pick off and destroy the affected leaves. 



This species is known also in France, Italy, and Austria. 



Sacc. Syll. iii. 3135 ; Cooke, Hdbk. No. 1300 ; Grevillea, xiv. 104. 



MAPLE-LEAF ASTEROMA. 

 Asteroma Aceris (Bob.). 



Forming spots on both surfaces of the leaves of Acer campestre. The 

 small perithecia are seated on very thin radiating brown fibrils, and 

 contain minute continuous sporules. 



Sacc. Syll. iii. 1234 ; Grevillea, xiv. p. 75, No. 444. 



MAPLE-TWIG BLIGHT. 

 Septoglaum Hartigianum (Sacc.), PI. XIX. fig. 3. 



This parasite occurs on the living twigs of Acer campestre, and the 

 year-old branches, especially those forming the crown, to the ultimate 

 destruction of the tree. In the month of May the cuticle of the diseased 

 shoots is split longitudinally, exposing the layer which bears the conidia. 



The pustules are at first innate, then erumpent, loosely gregarious, 

 oblong-linear, margined by the ruptured cuticle (1-2 mm. long). The 

 stroma is white, bearing on its surface the crowded conidia which are 

 ovate-oblong, with obtuse ends, almost straight, and typically two-septate 

 (42-36 x 10-12 ^u). The threads which bear the conidia are cylindrical 

 with an inflated base (30-35 x 6-7 /i), colourless. 



This fungus is really equivalent to what has been called Anthracnose, 

 with septate conidia. 



It is known also in Bavaria. 



It is recommended to cut out the diseased shoots in the beginning of 

 May. 



Sacc. Syll. xi. 3745 ; Mass. Dis. PL 297 ; Hart. & Som. Dis. Trees, 

 p. 141, fig. 80. 



Another species (Septoglwum acerinum) on living leaves of Acer 

 campestre is known in Italy, with curved trinucleate or biseptate conidia 

 (20 x 4 /^), and probably also in Belgium. 



