104 MICEOSCOPIC FUITGI. 



and stems are covered^ from the bean rust [Tricho^ 

 basis FabcBy Lev.)^ whicli in like manner is con- 

 sidered as the simple stage or form of tlie bean 

 brand {Pitccinia Fabce^ Lk.). If the legumes are 

 also examined^ a few pustules will sometimes be 

 found on them. Beans thoroughly infected with 

 this rust or brand are seldom of much service in 

 either field or garden. 



Beetroot^, or mangold wurzel^ is another example 

 of garden and field produce which is subject to a 

 similar visitation. This rust often has very red 

 spores when produced on red varieties of beet. 

 During September^ 1868^ it [Trichohasis Betce, Jjev.) 

 was sent us on the leaves of the wild beet {Beta 

 maritima). 



All the species of Polygonum are exceedingly 

 subject to the attacks of the Persicaria rust {Tri- 

 chohasis Polygonorum, B.)^ which nearly covers the 

 leaves^ till the entire plants seem to be smothered 

 in Scotch snuff*. If it were allowable to affirm of 

 any plants that they are martyrs to parasitism^ such 

 might be said of the Persicarias and their allies. 



Sedges are subject to the attacks of a rust much 

 resembling the corn rust. When it occurs on some 

 species of Garex, the upper surface of the leaf has 

 corresponding pale spots^ and the pustules them- 

 selves are surrounded by a yellowish margin. This 

 species {Trichohasis caricina) is far from uncommon 

 (plate VIII. figs. 170^ 171). The sedge-like plants 

 belonging to the genus Liizula have also their own 



