Thallogens.] 



FUNGALES. 



35 



works generally, to the various writings of Necs von Esenbeck, and to the Scottish 

 Cryptogamic Flora of Greville. In the ensuing list of genera, I have chiefly availed 

 myself of the writings of Fries. The disposition, however, of the genera has been modi- 

 fied in conformity with recent discoveries as to the real structure of the more highly 

 organised species, and the numerous discoveries of Corda, where their affinities were 

 at all clear, have been recorded. That it must be a matter of extreme difficulty to 

 form any precise opinion concerning Fungi, without long experience, will be apparent 

 from the observations of Fries upon the genus Thelephora. {Elenchv.s, p. 158.) 

 He asserts that out of mere degenerations or imperfect states of Th. sulphurea, the 

 following genera, all of which he has identified by means of unquestionable evidence, 

 have been constructed ; viz., Athelia of Persoon, Ozonium of Persoon, Himantia 

 of Persoon, Sporotrichura of Kunze, Alytosporium of Link, Xylostroma, Racodium 

 of Persoon, Ceratonema of Persoon, and some others. Th. Fr. Nees von Esenbeck 

 also assm'es us that the same fungoid matter which produces Sclerotium mycetospora 

 in the winter, develops Agaricus volvaceus in the summer. It would thus seem 

 that the opmions of those who have asserted that the species or genus of a Fungus 

 depends not upon the seed from which it springs, but upon the matrix by which 

 it is nourished, are at least specious ; especially if we take the above fact in 

 connection with the experiments of Dutrochet, Avho obtained different genera of 

 Mouldiness at will, by emplojing different infusions. He says that certain acid fluids 

 constantly y\e\di Monilias, and that certain alkaline mixtm'es equally produce Botrytis. 

 Ann. des Sc. 2 ser. 1. 30. For a description of the gradual development of an Agaric, 

 see this ingenious observer's Memoir in the Noiiv. Ann, du Mus. vol. iii. p. 76. For the 

 views of Unger upon spurious Fimgi, which he considers nothing but morbid condi- 

 tions (eruptions) of vegetable matter, see the Ann. des Sc. vol. ii. oi. s. 209 ; and 

 Berkeley's remarks thereupon, in Hook, Brit. Fl. vol. ii. pt. 2, p. 361 . 



Smce, however, the remarks of Unger were pubhshed, LdveiUe and Corda, almost at 

 the same time, and quite independently of each other, made their discovery of the 

 Mycelium of Uredines and Puecinite, and Corda has 

 succeeded in making many germinate. Unger's spe- 

 culations, therefore, must be considered as much in- 

 validated, at least so far as their bemg mere transfor- 

 mations of the cellular tissue, as is the case in Erineum. 

 Whether animal and vegetable bodies are ever pro- 

 duced without pre-existent germs, belongs to quite 

 another question. And, as regards the genera Ozo- 

 nium, Himantia, &c., they are now regarded by all 

 good mycologists as mere bancen states, or anamor- 

 phoses of other species ; and the same is probably true 

 of many of the more anomalous Fungi ; and the obser- 

 vations of Leveille, in the Annales des Sciences Natu- 

 relles, go very far to prove that the whole genus Scle- 

 rotium belongs to the same category. Some of them, 

 as Acrospermum cornutum, and Sclerotium myceto- 

 spora, are undoubtedly mere forms, and have no right 

 whatever to be considered as species ; others arise 

 from the condensation of the filamentous tufts of 

 moulds ; others, as S. lotorum, are little excrescences 

 upon the roots, and the celebrated Ergot is produced 

 by the action of a minute parasite. There is indeed a 

 difficulty about such species as Sclerotium scutellatum ; 

 but there is little doubt that, in the main, Leveille's 

 observations, even though from tlie nature of the sub- 

 ject the proof is not rigorous, are fomided in fact. 

 Some supposed species of Uredo are merely the young 

 of Puccinia, Aregma, &c. ; but there are also true 

 species of the genus. See Henslow, Journ. of Roy. Soc. 

 Ag. 1841, vol. ii. p. 2. 



KUtzing, in his Prize Essay on the Transformation 

 of Plants, asserts that from one and the same oi'ganic 

 material, even when it has acquired form and colour, different vegetables may be 

 developed, which, according to the circumstance of the surrounding medium, are 

 Algals, Fungi, Lichens, or Mosses ; and that even the spores of these, when pro- 

 Fig. XXIV.— Puccinia graminis (common Mildew), with its spawn or mycelium penetrating the cell 

 of the plant on which it grows. 



d2 



Fig. XXIV. 



