34 



FUNGALES. 



[Thallogens. 



have proposed to establish them as an independent Kmgdom, equally distinct from 

 animals and vegetables ; others have entertained doubts of their being more than 

 mere fortuitous developments of vegetable matter, called into action by special con- 

 ditions of light, heat, earth, and 

 air — doubts wliich have been 

 caused by some remarkable cir- 

 cumstances connected with their 

 development, the most material 

 of which are the following : they 

 grow with a degree of rapidity un- 

 known in other plants, acquiring 

 the volume of many inches in the 

 space of a night, and are frequently 

 meteoric, that is, spring up after 

 storms, or only in particular states 

 of the atmosphere. It is possible 

 to increase particular species with 

 certainty, by an ascertained mix- 

 ture of organic and inorganic mat- 

 ter exposed to Avell-known atmo- 

 spheric conditions, as is proved by 

 the process adopted by gardeners 

 for obtaimng Agaricus campestris, 

 a process so certain, that no one 

 ever saw any other kmd of Agaricus 

 produced in ISIuslu'oom-beds, ex- 

 cept a few of the dunghill tribe, 

 where raw dimg has been placed 

 near the sm-face of the bed ; this 

 could not happen if the Mushi'oom 

 sprang from seeds or sporules float- 

 ing m the air, as in that case many 

 species would necessarily be mixed 

 together ; Fmigi are often pro- 

 duced constantly upon the same 

 kind of matter, and upon nothing 

 else, such as the species that are 

 parasitic upon leaves : all which is 

 considered strong evidence of the 

 production of Fimgi being acci- 

 dental, and not analogous to that 

 of perfect plants. Fries, however, 

 whose opinions must have great 

 weight in all questions relating to Fungi, argues against these notions in the following man- 

 ner : " The sporules are so infinite (ua a single mdividual of Reticularia maxima I have 

 reckoned above 10,000,000), so subtile (they are scarcely \asible to the naked eye, and often 

 resemble thin smoke), so light (raised, perhaps, by evaporation into the atmosphere), and 

 are dispersed m so many ways (by the attraction of the sun, by insects, wind, elasticity, 

 adhesion, &c.), that it is difficult to conceive a place from which they can be excluded." 

 I give his words as nearly as possible, because they may be considered the sum of all that 

 has to be urged against the doctrine of equivocal generation in Fimgi ; but without ad- 

 mitting, by any means, so much force in his statement as is required to set the question 

 at rest. In short, it is no answer to such arguments as those just adverted to. It seems 

 to me that a preliminary examination is necessary into the existence of an exact analogy 

 between all the plants called Fungi ; a question which must be settled before any 

 fiirther inquiry can be properly entered upon. That a number of the fungus-hke 

 bodies found upon leaves are mere diseases of the cuticle, or of the subjacent tissue, is 

 by no means an micommon opinion ; that many more are UTegular and accidental 

 expansions of vegetable tissue in the absence of Hght, is not improbable ; and it is 

 already certain that no mconsiderable number of the Fungi of botanists are actually 

 either, as various Rhizomorphas, the deformed roots of flowering plants growing in 

 cellars, clefts of rocks, and walls ; or mere stains upon the surface of leaves, as Venu- 

 laria grammica ; or the rudiments of other Fungi, as many of Persoon's Fibrillarias. 

 Those who are anxious to inqiure into these and other points, are referred to Fries' 



XXIII. 



Fig. XXIII.— Aseroe pentactina. 



