Griffiths : A new Ergot 23T 



in each of the others but in diminishing quantities westward. The 

 smuts with which the grasses were as badly affected in the higher 

 altitudes were next to absent in the lower drier areas about Tucson 

 in the Santa Cruz. Only one species of the smuts mentioned, 

 and this in very small quantity on a single host, was found in the 

 latter locality. This species was found in two stations near Tucson, 

 one a poorly cultivated, irrigated field and the other a broad 

 shallow wash on the mesa, which received the drainage of a con- 



■ 



siderable area. The hosts were common, however, in places 

 within a radius of ten miles of Tucson. I think I have never met 

 with a more striking example of the effect of drouth on the de- 

 velopment of the smuts of native grasses. 



It must also be borne in mind that the period of development 

 of the parasitic fungi of this region is much shorter than it is in 

 the regions favored with a more equable distribution of rainfall. 



4 



Some of the hosts grow up and mature their seed in the short period 

 of two months after the advent of the summer rains. The life of 

 the fungus must likewise be subjected to the same shortening proc- 



Indeed the parasitic fungi like their hosts necessarily spring 



into activity when the summer rains come and follow the advent of 

 this agency as much as they do the seasonal variations of tern- 



perature. 



These remarks are equally applicable to the species of ergot 

 in question. There was plenty of the host {Hilaria mnticd) of 

 this interesting species found in the vicinity of Vale in the Santa 

 Cruz valley, but careful search was required in order to ascertain 

 the presence of sclerotia upon it, while they were exceedingly 

 abundant wherever the host was found in the Sulphur Spring Valley. 

 The space traveled over in the Hilaria region of the upper valley 

 is estimated to have extended in the aggregate a distance of at 

 least i 5 miles, where there were patches of the grass every few 

 rods. Scarcely any of it was free from the ergot. There was one 

 locality on the railroad right-of-way near Cochise where the fungus 

 was exceedingly abundant. The occurrence of an acre of grass 

 making an excellent stand of hay with scarcely a head free from 

 ergot would represent rather the extreme for the Agropyron and 

 Ely mas condensates regions of the Northwest. Yet this represents 

 exactly the condition on the so-called deserts of Arizona. The 



