172 



HARD WICKE 'S S CIE NCE - G SSIP. 



formerly almost all included in the genus Erysiphe, 

 have been divided into the following genera : — Peri- 

 sporium, Lasiobotrys, Spharotheca, Phyllactinia, Unci- 

 nitla, Podosphcera, Microsphezria, Erysiphe, Chcrto- 

 mium, Ascotricha, Eurotium. 



I will endeavour to describe the forms most usually 

 met with, and would refer any one who wishes for 

 fuller and more detailed information to Dr. Cooke's 

 " Rust, Smut, Mildew, and Mould," and to his 

 "Handbook of British Fungi," to the latter of which I 

 am indebted for the generic and specific descriptions. 



PERlsrORlUM, Kunze. Perithecia (conceptacles) 

 subglobose, without manifest mycelium or append- 

 ages ; spores numerous. The three species described 

 are far from common, and appear to approach in 

 character the neighbouring order Sphariacei. 



Lasiobotrys, Kunze. Erumpent, central peri- 

 thecia between fleshy and horny, proliferous, collaps- 



Fig. no. Phyllactinia guttata. 



ing above, attached to radiating fibres ; secondary 

 perithecia ascigerous ; asci cylindrical. There is only 

 one species, which is parasitic on living leaves of 

 Lonicera — L. lonicercc, Kze., which, though not com- 

 mon, appears widely distributed. It differs from the 

 rest of the order in being subepidermal. 



Spplerotheca, Lev. Perithecia globose, spring- 

 ing from an arachnoid mycelium, containing one 

 many-spored ascus. Sphrerotheca is distinguished 

 from Erysiphe by having a single many-spored ascus, 

 while the latter has several asci, each containing but 

 few spores. Appendages numerous, floccose. 



S. pannosa, Lev., the Rose Mildew, occurs on 

 leaves, petioles, &c. of roses. The conidiophorous 

 condition is extremely common, while the perithecia, 

 which are very minute, occur but very rarely. 



S. castagnei, Lev., which differs but little from 

 S. pannosa, is found on Hops, Meadow-sweet, &c. 



Phyllactinia, Lev. Perithecia hemispherical, 

 depressed ; appendages needle-shaped, stiff, and 

 brittle. 



P. guttata, Lev. Conceptacles large, easily distin- 

 guished by their straight acicular appendages. Occa- 

 sionally very abundant on Hazel, also on Ash, Elm, 

 Alder, Birch, Oak, Hornbeam, &c. (fig no). 



Uncinula, Lev. Perithecia globose ; appendages 

 numerous, simple, or dichotomous, always hooked. 



U. adunca, Lev. Perithecia scattered, small ; 

 appendages simple, hooked ; asci 8-12, containing 

 4 spores. On leaves of Willows, Poplars, Birch, &c. 

 Rather common (fig. in). 



U. bicornis, Lev. Mycelium effuse ; perithecia 

 rather large ; appendages bifid, hooked ; asci 8, 



Fig. in. Uncinula adunca. 



Fig. 112. Uncinula bicornis. 



containing 8 spores. Sycamore-leaves, — common, 

 (fig. 112). 



U. Wallrothii, Lev. Perithecia minute; asci 12-16, 

 6 spores ; appendages very long, hooked, simple. 

 Distinguished from U. adunca by the greater length of 

 the appendages (fulcra). 



Podosph^ra, Kunze. Mycelium arachnoid ; 

 perithecia globose, containing a single 8-spored 

 ascus ; appendages few, repeatedly dichotomous, 

 thickened at the extremity, hyaline. 



P. Kunzci, Lev. Perithecia minute, scattered, 

 globose ; appendages 3 times the diameter of the 

 perithecium. On plum-leaves. 



P. clandestina, Lev. Similar to P. Kunzei, but 

 appendages much shorter and more numerous. On 



