The Myxomycetes of the Miami Valley, Ohio. 



155 



kingdom (Gasteromyci) of his Vegetabilia mycetoidea (Pilze). 

 They constitute the " Circulus primus" under the name, 

 Aerogasteres ; they are sharply distinguished from the " Cir- 

 culus secundus," the Geogastri. Nees appears to be the first 

 writer to separate the Myxomycetes from the Puff-balls. 

 This same system appears in Martius's Flora Erlangensis. 



The third important work upon the Fungi is the Systema 

 Mycologicum of Klias Fries, in three volumes, 1821-1832. 

 In this work the Myxomycetes appear in the second class, 

 Gasteromycetes, under the title Myxogastres ; they constitute 

 the second sub-order of the third order, the Trichospermi. 

 Fries made himself familiar with the works of all his prede- 

 cessors, and with great care and nice judgment strove to ar- 

 range the synonymy. He studied diligently the " morphosis " 

 of the primary mucilaginous stage in the different genera of 

 the Myxogastres; he referred all the different forms to four 

 types, and sought to make use of these in classification. 

 Fries made but two additions to the genera of his predeces- 

 sors, but he redefined and more strictly limited all of them. 



The following is an outline of the sections and genera of 

 Fries's system : 



SUB-ORDER IL MYXOGASTRES. 



§1. AETHALINI. 

 Genus 14. Lycogala ; 15. Reticulata ; 16. Aethalium; 17. 

 Spumaria. 



%2. PHYSAREI. 

 Genus 18. Diderma ; 19. Didymium ; 20. Physarum ; 21. 

 Craterium. 



§3. STEMONITEI. 

 Genus 22. Diachea ; 23. Stemonitis ; 24. Dictydium ; 25. 

 Cribraria. 



§4. TRICHIACEI. 

 Genus 26. Arcyria ; 27. Trichia; 28. Perichaena ; 29. Licea. 



Under this system Fries described 192 species of the Myx- 

 ogastres. It remained the working system for more than 

 fifty years, and at the present time the specific forms recog- 

 nized by Fries are scarcely to be questioned. 



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