HIGHEE FUNGI. 135 



P. oxybaphi, Ell. and Kell. On various Nyctaginaceae. 



P. polygoni, ThUm. On Polygonum. 



P. euphorbiae, Fuck. On Euphorbia. 



P. urticae (Lib.). On Urticaceae. 



P. elliptica causes death of lilies. ^ 



B. Higher Fdngi (Mycomtcetes). 



The higher fungi are distinguished from the lower in possessing 

 a mycelium, which, from the first, is divided by means of cross- 

 septa. The mycelium of the lower fungi, though often much 

 branched, remains unicellular till cross-septa arise on formation of 

 reproductive organs or in the older stages of the fungus.^ In 

 higher fungi, septation begins with the first appearance of 

 mycelium and extends acropetally, growth in length proceeding 

 from the terminal cell. Sexual organs are without doubt present 

 in the lower fungi, but amongst the higher forms, Brefeld believes 

 that the sexual act no longer exists. On the other hand, certain 

 organs, found especially in the lichens, have been regarded as 

 sexual. 



Dangeard regards the union of cell-nuclei as a sexual act, 

 and assumes its existence in the asci and basidia of higher 

 fungi. His more recent investigations on the nuclei of fungi, 

 combined with those of Pairault and Eaciborski, have laid the 

 way to a new systematic arrangement.^ Just as amongst the 

 lower fungi the cell produced by a sexual act contains a nucleus 

 derived from the fusion of two nuclei of distinct origin, so amongst 

 the higher fungi one also finds cell-nuclei derived from copulation. 

 The investigations of Dangeard, Eosen, Wager, Pairault, and 

 Eaciborski, lead to the conclusion that : * "a stage may be 

 found amongst higher, as well as lower fungi, in which two 

 cell-nuclei of one cell copulate. The cells known as oospores 

 of the Oomycetes, zygospores of the Archimycetes and Zygomycetes, 

 ehlamydospores of the Ustilagineae, and teleutospores of the 



^ Smith, Disease of Lilies, 1888. 



^ Zopf. Die Pihe, 1890 ; and Beitrdge z. Physiol, u. morphol. niederer Organismen, 

 Heft III., 1893. 



* Dangeard. " Recherches sur la reprod. sexuell d. champignons ' Le 

 Botaniste, 189.S. Pairault and Raoiborski. "Sur les noyaux des Uredinees" 

 Jour, de Botanique, 1895. 



* Raoiborski. Mora (ergdnzungsband), 1895, p. 439. Compare also : Stras- 

 burger. " UeberperiodischeReduktion d. Chromosomenzahl im Entwickelungsgang 

 d. Organismen," Biol. Centralblatt, 1894, p. 862. Wager. " Nuoleaj: division in 

 the Hymenomycetes," Armals of Botany, 1893, p. 490. 



