SMUTS. 79 



and tlius year after year^ with as mncli certainty as 

 the grain upon which they are parasitic ? 



Like many of the parasitic fungi, so destructive 

 in the farm and the garden, this species belongs to 

 the family in which the spores are the distinctive 

 feature. After many botanical changes, the ^' smut ^* 

 is at length regarded as a fixed resident in the 

 genus Ustilago, with the specific name of segetum, 

 which latter signifies " standing corn ; " it is there- 

 fore the Ustilago, or sinut of the standing corn. The 

 characters of the genus are, chiefly, that the spores 

 are simple and deeply seated, springing from deli- 

 cate threads, or in closely-packed cells, ultimately 

 breaking up into a powdery mass. Eighteen mem- 

 bers of this genus have been described as British. 

 'One of these (JJ. maydis) attacks the maize or 

 Indian corn groAvn in this country in a similar 

 manner as the common smut attacks wheat or 

 barley ; but as maize is not an established crop 

 with us, a more minute description of this species 

 is unnecessary ; the spores are figured in plate V. 

 fig. 108. Another species (Z7. liypodytes) makes its 

 appearance at first beneath thfe sheaths of the leaves 

 surrounding the stems of grasses (fig*. 100), and 

 ultimately appears above and around them as a 

 purplish-black dust (fig. 101). The seeds of sedges, 

 theleavesand stems of certain definite species of grass, 

 the flowers of scabious (plate IV. figs. 123 — 125), the 

 Teceptacles of the goatsbeard, the anthers of the 

 bladder campion, and other allied plants, and the 



