INTRODUCTION TO CRTPTOGAMIC BOTANY. 301 



tragus of Montagne very probably includes such forms of 

 fruit. But not only are they destructive to vegetable tissues. 

 Where they penetrate into the intimate organs, as in the case 

 of the silkworm and several other insects, they soon produce 

 death. The muscardine, which is caused by Botrytis Bassiana, 

 is capable of being propagated by inoculation, or even without 

 any injury of the tissues the mere act of rubbing a few spores 

 upon the body is sufficient to propagate the disease. 



319. Moulds are peculiarly cosmopolites. The species, how- 

 ever, of tropical countries have at present been little studied, 

 but the commoner forms are found over the most distant parts 

 of the globe. The parasitic species of Botrytis attain their 

 highest perfection in America, as Botrytis viticola. Amongst 

 the black moulds some genera, as Campsotrichum, seem ex- 

 clusively tropical, and fine forms occur in the warmer parts of 

 the United States, but some of these may still turn up in 

 Europe, for one at least of the nobler species of Septonema, 

 which are produced in North America, has been found in great 

 perfection in Great Britain. Tropical leaves support a few 

 species besides those mentioned, not, however, in general 

 remarkable for beauty or pecuharity of structure, which do 

 not occur on the leaves of the plants of temperate climates. 

 Amongst the higher forms which present something hke an 

 hymenium, as Stilbwm, a few species affect tropical climes ; 

 but if S. lateritium and cinnabarinum, and one or two less 

 common species, are the ornament of tropical woods, we have, 

 by way of compensation, S. aurantiacum, Bab. TUl these 

 more obscure and minute Fungi shall have been well worked 

 out, it is impossible to come at any correct estimation of their 

 comparative frequency in the northern and southern hemi- 

 spheres. 



320. Few more beautiful objects are afforded for the micro- 

 scope, the elegance of which may be best estimated from an 

 inspection of the beautiful figures in Corda's Pracht-Flora. 

 Unfortunately, however, they are rather difficult of observation 

 from the quantity of air which they retain amongst their 

 branches, and their spores are often so loosely attached that 

 the slightest motion, or even the action of the water in which 



