SECT. I 



CRYPTOGAMS 



353 



layer, two to three cells deep, of pseudo-parenchyma. The genus Erysiplie, on the 

 other hand, develops in each perithecium several asci which arise in branches from 



the ascogenous hyphse. The perithecia 

 are irregularly ruptured at their apices 

 and the spores are thus set free. Before 

 entering upon the formation of perithecia, 

 the Mildew Fungi multiply by means of 

 conidia abstricted in chains from special, 

 erect hyphse, from the tip downwards. 

 The Mildew Fungus of the Grape-vine, 

 Erysiplie 1'uckeri, exhibits only such con- 

 idial fructifications ; its ascus - fruit has 

 not as yet been found in Europe. In its 

 conidial form, known as Oidium Tuckeri, 

 it is a highly destructive parasite ; to stop 

 its ravages it is customary to dust the 

 vines with sulphur and copper sulphate or 

 to sprinkle them with Bordeaux mixture 

 (a solution of lime and copper sulphate). 

 35 



Fig. 275. — Eitrolium herbariortim (= E. Asper- 

 gillus glaucus). A t Rudiment of the ascus- 

 fruit ; /, coiled, fertile hypha ; st, sterile 

 hypha 1 . ; B, young fruit ; p, wall of peri- 

 thecium formed of sterile hyphaa : C, a half- 

 ripe fruit with ripe asci (t^) and a number 

 of unripe asci (a{) '. B, conidiophore borne on 

 the mycelium ; c, conidia. (After Kny.) 



2. The Pcrisporieae are closely related 

 to the Erysipheae, but are saprophytic 

 and live on decomposing organic matter. 

 To this order belong two of the most 

 common Mould Fungi, Eurotium her- 

 bariorum and Penicillium glaucum. 

 Both at first multiply extensively by means of conidia before they begin to form 

 perithecia. 



In the ease of Eurotium herbariorum, the conidia are abstricted in chains from 



2 A 



Fig. 27(5. — Pencilliuiii crustaceum. Conkliophore 

 with verticillate branches (s', s") ; b, st, sterig- 

 mata abstricting chains of conidia. (From an 

 alcohol-h hematoxylin specimen, x 540.) 



