168 MICKOSCOPIC FUNGI. 



■^ight ; in tlie grass mildew, and some others, 

 flumerous. The tips of the appendages are variable, 

 and often elegant (figs. 227, 231, 233, 234, and 

 247), sometimes simple and at others symmetrically 

 branched. All the species occur on the stUl 

 living and green parts of plants, especially the 

 leaves, and are therefore truly parasitic. A pocket 

 lens win show whether any conceptacles are present 

 on any suspicious leaf which may be collected, but 

 high powers of the microscope are essential for 

 their complete examination. It is during autumn, 

 when vegetation begins to languish, that we shall 

 be most successful in searching ' for specimens. 

 Tliey will then be found almost everywhere, and 

 the white myceUum forms an object too conspicuous 

 for them to be readily overlooked. Botanically, 

 nearly all the species were at one period included 

 in one genus, under the name of Erysiphe, a name 

 derived from the Greek, and signifying " mildew ;" 

 at the present time they are distributed through 

 several genera, the chief distinctions of which are 

 based upon the form of the appendages. Though 

 personally disposed to question the generic value of 

 such distinctions, it would be imprudent to adopt 

 any other names here than those to be found in 

 recent BngHsh works on fungi. 



The first species in our enumeration is found on 

 cultivated roses. What a deplorable picture does 

 a favourite rose-bush present when attacked by this 

 mildew ! The leaves blistered, puckered, and con- 



