General. 



Various observations as to the effect of parasitic fungi 

 upon tlie flowers of the host are summarized by von Tubeuf.d) 



Owing to the extent of gall formation induced by the 

 fungus, it is not possible to say if ovaries are actually developed 

 in male flowers of Spinifex hirsutus (cf. the cases cited by 

 Tubeuf of Carex praecox with U . caricis, Buchloe dactyloides 

 with T. huchloeana, and Andropogon provincial is with V. 

 andropogonis). But in place of the normally abbreviated 

 floral axis a more or less extensive smut gall is developed, 

 resembling that formed in the female flower, except that in 

 the male inflorescences it is usually somewhat smaller. A 

 similar prolongation of the axis is seen in the axil of the third 

 glume of the female spikelet. This glume, it will be remem- 

 bered, is either sterile or subtends a male flower in the healthy 

 inflorescence. 



In a paper on Tilletia foetens, Barrus(2) cites observa- 

 tions by Edler, Appel, and Miczynski upon wheat affected by 

 stinking smut to the effect that the diseased heads are looser 

 than normal and of greater length, though Barrus' own 

 observations showed that the infected heads were rather 

 shorter. He notes that more grains are found in a smutted 

 ear of wheat than in a normal one of equal length, there being 

 more ovaries per spikelet in the former case. So in Spinifex 

 hirsuttos two smut masses form per female spikelet, though 

 the healthy flower has but a single ovary. 



The most obvious pathological deformation is the com- 

 plete absence of the long sterile axes or spines of the normal 

 female inflorescence. Thus the smutted head has not the 

 same potentiality for distribution as the healthy one, for it 

 cannot roll about in the same way. It was probably this 

 feature that led to the earlier recognition of the fungus on 

 the female plants. More interesting is the development of 

 structures resembling those formed in female flowers upon 

 the male, which, though they are not so definite as in the 

 case of the smuts, referred to above, yet seem to merit brief 

 description. 



DESCRIPTION OF PLATE I. 



Fig. 1. Male inflorescence of Spinifex hirsutus infected with 

 Cintractia spinificis, showing the reduced number of spikelet- 

 bearing axes and an increase in the number of spikelets above 

 the normal. 



Fig. 2. Female inflorescence of S. hirsutus with C. spinificis, 

 showing the looser structure, the absence of long sterile spines, 

 and the spikelets some 2 cms. above the base of the spikelet- 

 bearing axes, abnormalities due to the presence of the fungus. 



(1) Tubeuf and Smith, ''Diseases of Plants," 1897, pp. 26-29. 



(2) Barrus, M. F., ''Observations on the Pathological Morph- 

 ology of Stinking Smut of Wheat," Phytopathology, vi., pp. 21-28, 

 1916. 



