i68 



MYCOLOGY 



dark brown to paler brown apothecium, i to 4 cm. across and almost 

 stemless. P. ceruginosa is a stalked, green form whose mycelium pene- 

 trates the wood of beeches and oaks and imparts to them a copper- 

 green color, which makes it valuable for the manufacture of the famous 

 "Tunbridge ware." The attempt has been made to extract the pig- 

 ment, or to manufacture it synthetically for use as a shingle stain, but 

 without much success. P. Willkommii produces on larch trees a disease 

 known as larch canker. Other species of Peziza grow on bark (Fig. 59), 

 horse and cow manure, and are, therefore, typically coprophilous. 

 Family 6. HelotiacE/E. — The apothecia in these fungi are super- 

 ficial from the beginning and rarely arise by break- 

 ing through the substratum. Sometimes they de- 

 velop from a sclerotium {Sclerotinia). In texture, 

 they are waxy, leathery and thick, and stalked, or 

 unstalked, smooth or hairy. The asci are eight- 

 spored. The spores are round, elongated, or fila- 

 mentous, and one to eight-celled, hyaline. The 

 paraphyses are filamentous. The fringe cup, 

 Sarcoscypha floccosa, has a slender, white, hairy 

 stem, I to 3 cm. long by 2 to 3 mm. wide, and 

 bearing an apothecium 4 to 10 mm. wide with a 

 scarlet disk, so that the whole fruit body is goblet- 

 shaped. The outside of the cup is covered densely 

 with long white hairs forming a fringe at the margin. 

 The spores are clear and elliptic 20 by 11//. The 

 -Scleroiinia fringe-cup fungus grows on decaying twigs from 

 spring to autumn. Sclerotinia is the most impor- 

 tant genus economically. It includes about forty 

 species. The apothecium arises from a sclerotium. Sclerotinia haccarum 

 forms sclerotia in the fruits of Vaccinium myrtillus; S. urnula (Fig. 71) 

 in those of Vaccinium vitis-idcea. Sclerotinia Fuckeliana forms sclerotia 

 on the grape-vine. Its conidial form was long known as Botrytis cinerea. 

 Sclerotinia sclerotioriim (Fig. 60) is parasitic and pathogenic on a number 

 of cultivated plants, such as beets, and bears its sclerotia forming on the, 

 subterranean parts of these host plants. The black disease of hyacinth 

 bulbs is connected with the growth of Sclerotinia hulhosum. Apples, 

 pears and stone fruits are attacked by S. fructigena. S. libertiana. 

 causes lettuce drop. S. trifoUorum is responsible for the stem rot of 



(After 



