ALBU GIN ALES 10$ 



Jones, L. R., N. J. Giddings, and B. F. Lutmax, "Investigations of the po- 

 tato fungus, Fhytopbthora infestans,^'' U. S. Dept. Agr. Bur. Plant bid. 

 Bull, 245. 100 pp. 1912. 



Matthews, Velma D., Studies on the genus Pytbiwu. 136 pp. The Uni- 

 versity of North Carolina Press. 1931. 



MiDDLETON, J. T., "The taxonomy, host range, and geographic distribution 

 of the genus Pvthium," Mem. Torrey Botan. Club, 20: 1-171, 1943. 



MiYAKE, K., "The fertilization of Pytbiwu de haryanmn^'' Ann. Botany, 

 l)':65y-666, 1901. 



Petersen, H. E., "An account of Danish fresh-water Phvcomvcetes, with 

 • biological and systematic remarks," Ann. MycoL, 5': 494-560, 1910. 



Seal, J. L., "Coconut bud rot in Florida," Fla. Agr, Expt. Sta. Bidl., 199: 

 87 pp. 1928. 



Smith, R. E. and Elizabeth H., "A new fungus of economic importance," 

 Botan Gaz. ^2; 215-221, 1906. 



SxMith, Worthington G., "The resting spores of the potato fungus," Gard. 

 Cbron., n.s., ^; 68-70, 1875. 



Somaierstorff, H., "Eine Tiere fangender Pilz (Zoopbagus insidians, nov. 

 gen., nov. sp.)," Oest. Bot. Z., 61:361-373, 1911. 



Tucker, C. AL, "Taxonomy of the ^enus Phytophthora de Barv," Mo. 

 Agr. Expt. Sta. Researcb Bidl, 153. 208 pp. 1931. 



ALBUGINALES 



The Albuginales, commonly called "white rusts," comprise 

 a single genus, Albugo, having approximately 25 species. All are 

 obligate parasites of flowering plants, and none has been cul- 

 tivated on artificial media. They are an aberrant group, dis- 

 tinguishable mainly on the basis of their host relations. For 

 example, A. Candida is limited to various species of crucifers, 

 A. bliti to species of Amaranthus, A. ipovweae-paiiduraiiae to 

 morning-glory, sweet potato, and other Convolvulaceae, A. 

 tragopogonis to salsify and other Composites, and A. portidacae 

 to Portidaca oleracea. Usually none occurs in epidemic pro- 

 portions on crop plants, except perhaps A. Occident alls, recently 

 reported [Wiant, Ivanoff, and Stevenson (1939)] on spinach. 

 Whether this pathogen occasions real harm is questionable. 



Certain of these species comprise rather \\'idely different mor- 

 phological groups of entities that have been regarded as biological 

 species. By means of biometrical studies Togashi, Sibasaki, and 

 Sugano (1930) were able to show that the sporangia of A. Can- 

 dida on Brassica and Raphanus have measurements approximately 

 25% greater than those on Arabis, Capsella, and Draba. Their 



