A HISTORY OF DURHAM 



ash. The large pufF-balls Lycoperdon giganteum and h. ccelatum^ the 

 somewhat rare Cynophalliis caninus^ and the Geasters, may be specially 

 mentioned among the Gasteromycetes. Five species of Geaster have 

 been recorded, none of which are common, and one, G. mammosum, is 

 extremely rare. 



In the large order Vredinacece (the rust-fungi) many species are 

 found accompanying their hosts through the various changes of altitude. 

 Thus Puccima betonka preys upon the betony at its highest limit in 

 Burnhope, as well as near the coast, and similarly Mcidium tussilaginis is 

 found abundantly wherever the coltsfoot grows. The leaves of the wild 

 grasses and cereals are especially liable to the attacks of rust. 



Among the Ascomycetes the species of 'Taphrina cause the well-known 

 ' witches-brooms ' on the birch and cherry. The Erysiphacece are com- 

 mon as mildews upon the grasses and other plants. Nectria reveals its 

 presence by its small red pustules on decaying twigs, and as the destruc- 

 tive parasite associated with the canker of the ash, apple, and beech. 

 Epichke typhina, with its bright orange stroma, is frequently to be observed 

 destroying the inflorescences oi Dactylis glomerata and other grasses. The 

 small perithecia of various species of Sphceriacece are especially common, 

 being present on nearly every decaying stalk. The black stroma tipped 

 with snowy white of Xylaria hypoxylon form conspicuous objects in most 

 woods in winter. Rhytisma acerinum betrays itself by the black blotches 

 to be seen on the sycamore leaves which are everywhere attacked by this 

 fungus. The dark-coloured gelatinous cups of Bulgaria inquinans cover 

 the bark of fallen oak branches. The larch-canker fungus {Dasyscypha 

 Willkommii) is frequent in the larch plantations, and threatens to render the 

 cultivation of this tree impossible for any useful purposes. The curious 

 little black tongues of Geoglossum glabrum are fairly common, springing up 

 freely in grassy places. The rare Peziza onotica known as the ' orange-ear 

 peziza,' as well as P. melastoma, the black and red peziza, another rare 

 species, are found in the county, while the glowing crimson cups of 

 P. coccinea are common on decaying twigs. The species of Morchella are 

 also prevalent in the woody districts, the edible form, M. escuknta, being 

 not unfrequent. 



Among the Mesomycetes some species of Ustilago, the smut of the 

 cereals, cause annually a large loss. Among the Phycomycetes may be 

 mentioned Cystopus candidus, the ' white rust ' of cruciferous plants, growing 

 especially on Capsella bursa-pastoris ; Peronospora parasitica^ a parasite often 

 associated with Cystopus candidus; and Phytophthora infestatjs, the too well 

 known disease of the potato. The cruciferous crops are often devastated 

 by club-root (anbury) caused by P lasmodiophora brassica, one of the 

 Myxomycetes. 



Rare species not already mentioned are : Agaricus petaloides, A. 

 horizontalis, A. spartcus, A. gossypitius, Hygrophorus obrusscus, Cantharcllus 

 cinereus, Mcrasmius foctidus, Lentinus tigritius, Patius cotichatus. Boletus 

 castaneus, Tramctes pini, Dfcdalea co?ifragosa, Thehphora biemiis, 'TremeUa 

 frondosa, and T. vesicaria. 



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