fo 
Far and away the most important to us, however, is the form on 
Wheat, which is confined to Wheat, and does not even go to [Triticum 
repens. [che importance of this fact is obvious, for in the first place 
there is no fear of Wheat mildewing adjacent fields of Barley, or Rye, 
or Oats, or being mildewed by them; nor, in the second place, is 
there any fear of the Wheat catching the disease from mildewed 
grasses in the hedge-banks, &c. Bear in mind that, although these 
six forms are morphologically indistinguishable, either in their zcidio- 
spore, uredospore, or teleutospore stage, yet they are biologically 
distinct. Briefly, we have to deal with a form on Wheat, another 
on Oats, and a third common to Oats, Barley, Rye and Twitch, the 
other three forms being of botanical interest only. 
In the same way the authors found that P. rubigo-vera D.C., was 
divisible into three good species, viz., P. glumarum Sch.; P. dispersa 
E. & H.; and P. simplex Korn. Let us say a word or two about 
these seriatim. 
P. glumarum (Schmidt), the yellow rust or spring rust, as we often 
call it in England, possesses well-marked characters in its uredo stage, 
by which it can be recognised with the naked eye, inasmuch as the 
minute uredospore-beds occur on large elongated yellow patches on 
the leaves. _ The teleutospores are scanty in proportion to the uredo, 
and the sori minute. 
This rust owes its chief interest to two things : First, its great 
abundance and its conspicuousness alarm the Wheat-grower, making 
him think that his crop is going to be “mildewed,” whereas, in reality, 
it rarely causes any appreciable diminution of the yield. Secondly, 
because it has the habit of sometimes developing its uredospores upon 
the chaft (Cosh) of the affected Wheat-plants, hence its specific name 
—Uredo glumarum. When this happens, it does injure the crop, 
because the uredospores spread from the chaff to the kernels them_ 
selves, causing them to be distorted, and more or less abortive. On 
many of these damaged kernels one can find spore-beds of the teleuto- 
spores when the grain reaches maturity. 
: Ina similar manner, P. glumarum is met with in five specialised 
aie viz., Tritici, Secalis, Hordei, Elymi, and Agropyri, on Wheat, 
ye, Barley, Elymus, and Triticum repens respectively. 
Puccinia dispersa EK & A “Phe brown maeeis not nearly so con- 
Spicuous, nor is it so abundant as P. glumarum. It is met with later 
in the season in England, not long before harvest. «Whe sivede cori 
are like immature spore-beds of the uredo of P. graminis, only they 
