MICROSCOPIC OBJECTS. 47 



Fig. 93. Mould from a Decayed Leaf of Begonia (Botrytis 

 vera), x 40. 



Another kind of microscopic Fungi are the moulds, of 

 which this species is an example ; they are chiefly found on 

 decaying vegetable substances. 



The disease called the potato-blight is a mould, and be- 

 longs to this genus. Without doubt the spores of many of 

 the moulds enter the stomata of the leaves of plants, and are 

 thus carried with the sap into all its parts; and if there is 

 any inherent weakness which would be favourable to their 

 growth, they increase accordingly. That the spores of Fungi 

 thus enter into the circulation of plants may be shown by 

 mould being found in the interior of apples &c. Moulds and 

 various Fungi may be cultivated in a damp atmosphere, pro- 

 duced by covering damp sand or earth with a bell glass, such 

 as those used by gardeners, the sand being kept constantly 

 moist. 



The different moulds show best when mounted in a deep 

 dry cell. 



Fig. 94. A Species of Confervoid Algce (Spirogyra decimina), 



x!20. 



Of this species of Conferva, collected at Hollingbourne, 

 near Maidstone, the spiral bands are two, crossing each other 

 so as to present the appearance of a repetition of the letter X 

 joined together; and from this characteristic it is that the 

 species is named. The genus also is named Spirogyra from 

 the spiral bands which are always found, generally numbering 

 from one to four, according to the species. Some of the 

 species being rather common, and more particularly their 

 remarkable appearance, have caused them to be well studied. 

 The process of conjugation of the Confervse may be well seen 

 in ripe specimens of this genus. 



It is best mounted in a suitable fluid. 



