630 THE SMALLER FUNGI. 
mildew, magnified ; ¢, single spore of corn mildew, Puccinia 
graminis, magnified 300 diameters. From Cooke), but as 
this is so common, let it serve as an example of the whole. 
If bent on investigating this rust, you will seek it in its first 
stage, in the form of yellowish elongated pustules, when it 
constitutes the Trichobasis rubigovera of the French botanist 
Léveillé, and distinguished by one-celled yellow spores, with 
thickened outer coverings, and supported on short peduncles, 
which shortly fall away. Later in the season, brown pustules 
may be observed on the leayes and stems of the same grass 
plant, and in these, when ripened, the ‘spores are black, club- 
shaped, slightly constructed, and transversely divided by a 
septum, the peduncle or footstalk being distinct and perma- 
nent. Common as this pretty fungus is, it will repay atten- 
' tion in its microscopical study. In England by a strange con- 
fusion, such indeed as exists elsewhere among the unlearned, 
the first condition of this smaller fungus is termed the Rust, 
while the second is called Mildew. Allowing this latter 
name as applied to the Puccinia, “there is no doubt that the 
mildew is very injurious to the corn (grain) crop. Differ- 
ent opinions may exist as to how the plants become inocu- , 
lated, or how the infection may be prevented or cured. — 
_ Weare not aware that this question has been satisfactorily 
determined. It is worthy of remembrance by all persons 
interested in the growth of corn (grain), that the mildew 18 
most common upon plants growing on the site of an old 
dunghill, or on very rich soil. As the same Puccinia is also 
to be found on numerous grasses, no prudent farmer will 
permit these to luxuriate around the borders of his fields, 
lest they should serve to introduce or increase the pest he s0 
much dreads.” (pp. 54, 55.) 
I once had brought to me some stems of barley, 8° much 
infested with this little parasite, that the entire crop of 
straw anticipated was most materially injured. In some sèa- 
sons scarcely any of the firmer and coarser leaved grasses 
escape its visits. Search for other species of this singularly 
