K.—BOTANY 177 
Thanks to the researches of Stakman and Levine! in the United 
States, Newton and Johnson?* in Canada, Waterhouse 1® in Australia, 
Macdonald? in Kenya, Mehta 38 in India, and Verwoerd ? in South Africa 
much is now known about the physiologic forms of Puccinia graminis on 
wheat. Johnston and Mains 2° in the United States, Scheibe 24 in Ger- 
many and Mehta” in India have described many forms of Puccinia 
triticina, Gassner and Straib 2° in Germany have shewn that Puccinia 
glumarum consists of a complex of forms, and so on with many other fungi 
which are obligate parasites. Work has been proceeding recently at 
Cambridge concerning the physiologic forms of Puccinia triticina, P. glu- 
marum and P. coronata which occur in Britain. With P. triticina and 
P. glumarum several forms have been determined which have not hitherto 
been described on the Continent of Europe or elsewhere notwithstanding 
the great attention which has been paid to these fungi. This is a some- 
what surprising result and points perhaps to independent mutational 
changes here. 
An interesting question of nomenclature has arisen out of Gassner and 
Straib’s investigations on Puccinia glumarum. Many years ago Eriksson,” 
who was the pioneer investigator of specialised parasitism in the Cereal 
Rusts, divided P. glumarum into P. glumarum Tritici, P. glumarum Hordet, 
P. glumarum Secalis, etc., thinking that each trinomial indicated a distinct 
physiologic form. More recently it has been held that P. glumarum 
Tritici, for example, comprises a number of forms, all of which were 
thought to be confined to wheat. Gassner and Straib,2° however, have 
now shewn that this trinomial nomenclature is invalid, for some forms of 
P. glumarum will readily infect wheat, barley and rye provided that the 
variety range of each cereal is sufficiently extensive. Whether the same 
considerations apply to the nomenclature of Puccinia graminis is not yet 
known. Here there are P. graminis Tritici, P. graminis Avene, P. graminis 
Secalis, etc., each containing many forms. Certain forms of P. graminis 
Tritici and P. graminis Secalis are known to infect some barley varieties, 
and Mehta 2® shewed that P. graminis Secalis in England would infect a 
variety of wheat called Red Sudan. Logically it might be desirable to 
drop the trinomial nomenclature for P. graminis, but owing to the immense 
number of physiologic forms of this fungus it will probably be found 
convenient to retain it. 
In other types of parasitic fungi, including species of Fusarium which 
infect the underground parts of their hosts, distinct physiologic forms or 
14 Minnesota Agr. Exp. Sta., Tech. Bull. 8 (1922), 
i5 Dept. Agric. Canada, Bull. No. 160, N.S., (1932). 
16 Pyoc. Linn. Soc. of New South Wales, 54, p. 615 (1929). 
17 Tyans. Brit. Myc. Soc., 18, p. 218 (1933). 
18 Indian Jour. Agric. Sct., 8, Pp. 939 (1933). 
19 S. African Jour. Science, 28, p. 274 (1931). 
20 U.S. Dept. Agric., Tech. Bull. No. 313 (1932). 
21 Ayb. a. d. Biolog. Reichsanst., 18, p. 55 (1930). 
22. loc. ctt: 
23 Ayb, a. d. Biolog. Reichsanst., 21, p. 121 (1934). 
24 Ber. d. deut. bot. Ges., 12, p. 292 (1894). 
25 Joc. cit. 
26 Tyans. Brit. Myc. Soc., 8, p. 142 (1923). 
