— 310 — 



young shoots, in a number of c. 25, had reached a length ol" c. 6 ctm., 

 and roots, 4—5 cm. in length, had developed at their base. The 

 plants were looking entirely fresh. Having in the beginning of June a 

 length of c. 15 cm. and a quite normal and sound aspect, the plants will 

 evidently not be infected by the fungus, and it must thus be considered 

 as proved that Mijriophyllum aUerniflorum cannot at all be infected by 

 Cladochytrium Myriophylli Rostr. 



As to the systematic place of the fungus, its development shows that 

 it must be referred to the family Cladochytriaceae^ and the supposition 

 of P. Magnus (Rostr up 1. c.) that the fungus in question should be 

 allied to the TJstilag'maceae has thus turned out not to be right. The 

 generic name Cladochytrium can be upheld, when it is taken sensu latiori. 

 The fungus however represents a particular type (cp. the germination), 

 which is not fully congruent to that of any subgenus existing. 



Protobasidiomyceteae. 



Sebacina caesia (Pers.) Tul. 



In the fall 1908 we found this species on a soaky road through a 

 wood near Gurre in northern Sealand, where it covered the soil 



over ca. 10 cm. in length as 

 a grayish blue waxy crust. 

 By microscopical examination 

 of the material we found an 

 interesting character, which 



— as far as we are aware 



— is not stated in the my- 

 cological literature, this name- 

 ly, that the hyphae of the 

 hymenium by sympodial 

 growth perpetually are for- 

 ming new basidia and thereby 

 working out a gradual thicke- 

 ning of the crust. The lower 



basidia in such a sympodium are always seen to be decaying, the middle 

 ones are about the maturity and the upper ones still unpartited and 

 without sterigmata (see the fig.). 



As it was interesting to know, whether the same occurred in Seba- 

 cina incrustans (Pers.) Tul., we examined some specimens of this fungus, 

 collected by E. Rostrup (on Rubus caesius L. from Skaarup, Funen^ 



Fig. 2. Sebacina caesia (Pers.) Tul. 



Basidia on different stages of development C^/i). 



