392 Lecture on the Parasitic Fungi of the British Fai 



m. 



here depicted ; and a good idea may be formed from inspecting the 

 drawing, of the character of this fungus, as exhibited by the micro- 

 scope. " Thev put out fibres, which lift tliem up from the surface 

 of the leaf, and are preceded by threads, white or greyish, consisting 

 of bead-like joints, of which it seems the uppermost fall off and grow. 

 Beans are injured by a uredo — the uredo of the bean — which 

 was very prevalent last year. 



Vetches are attacked by a fungus styled hotrytis, from the 

 Greek Corpus, a bunch of grapes, because the spores grow in this 



way. (See fig. 13.) This drawing 

 shows a minute portion very highly 

 magnified^ and will convey a just idea 

 of its appearance and of the cause of 

 its name. It is called the botrytis of 

 the vetch, but in some places it attacks 

 peas and lucerne, and it might there- 

 fore bear the name of the leguminous 

 botrytis. Botrytis is distinguished from 

 other moulds, which are articulated, 

 and so named monilia or necklace 

 moulds, by it not having its threads 

 jointed. 



Dutrochet first stated, and I have 

 verified it myself by a series of experi- 

 ments detailed in my little work on the 

 blights of the wheat,* that if a single drop of almost any acid is 

 mixed with albumen, in eight or ten days necklace moulds appear ; 

 but, on the other hand, caustic alkali gives botrytis. With fibrine 

 of blood and phosphoric acid, the results are reversed. Every 

 sort of vegetable matter I tried with acid yielded a mould, but 

 when albumen contained a neutral salt none appeared. If sails of 

 mercury are present the development is stopped; aethiops mineral 

 does not check it; oxide of lead hastens it; oxides of copper, 

 nickel, and cobalt, retard it ; oxides of iron, antimony, and zinc, 

 have no effect; all perfumes stop it. Flowers of sulphur effec- 

 tually check the erysiphe on the peach, but they could not be 

 applied to pea-fields. How far a knowledge of the facts I have 

 just stated ma}^ lead to a remedy, easily applied in the shape of 

 manure, future experiments may show. 



in. These observations naturally lead to the botrytis iifestans, 

 found on the leaves of the potato when suffering from the true 

 murrain. The mycelium of this fungus traverses the entire 

 cellular structure of the plant, and emerges from the stomata 

 of the leaves, choking them, and the consequence is decay. 



Botrytis of the Vetch. 



* The title is " Blights of the Wheat ftiid their Remedies. 



