[Vol. 2 



408 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



NAME, SYNONYMY, AND MATERIAL EXAMINED 



Since the investigations of the brothers Tulasne many 

 mycologists have studied the violet root felt fungus on its 

 various hosts, especially on crocus, alfalfa, and certain root 

 crops. There is general, though not complete, agreement in 

 confirmation of the view that the crocus and the alfalfa forms 

 are identical, and that this species, R. Crocorum, occurs on 

 numerous hosts. I shall indicate later some of the morpho- 

 logical details in which the two forms agree and give other 

 evidence supporting the view of a single species. For the 

 present it is necessary to anticipate this evidence in order to 

 state that until a perfect stage is definitely established, it 

 would appear that the correct designation of the violet fungus 

 is Rhizoctonia Crocorum (Pers.) DC. As noted above, the 

 specific name applied by Persoon was adopted by De Candolle 

 when he established the genus. This name, perhaps unfor- 

 tunately, has priority over R. Medicaginis DC. in that it is 

 mentioned first by Fries (1823). Though necessary, it may 

 seem unwise to call the fungus R. Crocorum, inasmuch as it 

 is far more widely distributed on alfalfa; and, furthermore, 

 because its dicotyledonous hosts are more numerous. R. vio- 

 lacea would be a most appropriate descriptive name, but it 

 is obvious that this also would not conform to the rules. The 

 following provisional synonymy has been collated: 



Tub 



(1791) 



Sclerotium Crocorum Pers. (1801), 

 Rhizoctonia Crocorum DC. (1815), 

 Rhizoctonia Medicaginis DC. (1815), 

 Thanatophytum Crocorum Nees. (1816) 

 Tuber Croci Duby (1830), 

 Rhizoctonia Rubiae Dene. (1837), 

 Rhizoctonia Dauci Rabenh. M859^ 



Rh 



(1862), 



Rhizoctonia Asparagi Fckl. [non Fr.] (1869), 

 Hypochnus violaceus Eriks. (1913). 

 The identity of Rhizoctonia Crocorum DC. and R. Medi- 

 caginis DC. suggested by the brothers Tulasne ('62) and 

 accepted by most taxonomists, has been confirmed by a study 



