SMUTS. 79 



and thus year after year, with as much certaiiity as 

 the grain upon which they are parasitic ? 



Like many of the parasitic fungij 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 Usiilago, with the specific name of segetum, 

 whichrlatter signifies " standing corn ; " it is there- 

 fore the Ustilago, or smut 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 iato a powdery mass. Eighteen mem- 

 bers of thisgenus have been described as British. 

 One of these {JJ. maydis) attack^ the maize _Qr 

 Indian corn grown in this country in a similar 

 manner as the common smut attacks wheat or 

 barley ; but as maize is not an estabhshed crop 

 with us, a more minute description of this species 

 is unnecessary ; the spores are figured in plate V. 

 fig. 108. Another species {U. hy^odytes) jn.ak.es its 

 appearance at first beneath the sheaths of the leaves 

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

 ultimately appears above and around them as a 

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

 theleavesandstemsof certain definite speciesof grass, 

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

 receptacles of the goatsbeard, the anthers of the 

 bladder campion, and other allied plants, and the 



