iqi2] WOLF—ACTINONEMA ROSAE 223 



A. padi and A. crataegi, the latter showing at length peri 

 like structures, but no conidia were observed. In 18 29 17 he em 



5 name 

 renomy 



Later 18 he characterized the 



m 



thecium 



and lists A. rosae as one of the 



species which often possesses only a sterile mycelium. Saccardo 19 

 employs these characters as given by Fries and notes that the 

 fruits have not been observed in many species. Of the 18 species 

 of Actinonema which have been described, there are 8 species in 

 which the snores were not observed at that time. The radiating 



mycelium 



em 



character as originally given by Persoon. Lindau 20 includes in 

 Actinonema astomate pycnidial forms occurring on leaves. The 

 pycnidia arise from radiately actinic strands of mycelium. 



The genus Marsonia is characterized by having a subepidermal 

 acervulus, in which are produced hyaline, 2-celled conidia, very 

 similar to the conidia of Actinonema. Several species of Marsonia 

 have been described, however, in which the acervulus is subcuta- 

 neous, as Marsonia baptisiae E. & E., M. panatoniana Berl., and 

 M. fructigena (Rick.) Berl. Briosi and Cavara recognized the 

 true morphology of the rose Actinonema acervulus, but attached 

 no significance to the fact that it was subcuticular and not subepider- 

 wa/. The Actinonema-like character of the mycelium was not 

 taken into account by them as indicative of generic position. 



same 



Marsonia 



e subepidermal acervulus has been made one 

 acters of Marsonia, it would seem that these 

 might nronerlv be Dlaced in this genus. On 



other 



species of Actinonema. If we accept Persoon's 



' Fries, Elias, Systema Mycologicum 3:266. 1829. 



18 



, Summa veg. Scand. 424. 1849. 



19 Saccardo, P. A., Syll. Fung. 3:408. 1884. 



20 Lixdau, G., Engler and Prantl's Pflanzfam. i:399- l8 99- 



