92 SALMON : SUPPLEMENTARY 
S. pannosa on apple trees, the same mistake in identification has 
in all probability been made. 
The fungus known as the “peach mildew” is apparently S. 
pannosa, although some writers, ¢. g., Waite and Bailey refer it to 
Podosphaera oxyacanthae (see p. 85). This doubt as to the specific 
identity of the mildew on the peach is due probably to the fact 
that—as in the case of Podosphaera leucotricha on the apple—the 
conidial stage, which causes the injury, is usually the only stage im 
which the fungus occurs. I have, however, seen in a European 
example, the pannose mycelium of the perithecial stage of 5. 
pannosa on the stem of a peach tree. 
Smith (Journ. Mycol. 7: 90, 91. 1892, and Selby ('75*) both 
refer to the “ peach mildew” as “ S. pannosa,” and give the fol- 
lowing accounts of the injury caused by it. Smith observes: 
“This mildew usually attacks the leaves and young stems. On 
the latter it forms a dense, felt-like, persistent hyphae-complex 
which is first white and afterwards a dirty gray, the epidermis being 
cracked open and destroyed or much injured and a thick brow? 
layer of cork being formed, under the mycelial patches. The 
mildew produces conidia in abundance, but perithecia have a 
been found, although the search has been continued into winter.’ 
Smith noticed that the disease recurred. year after year upon the 
same individual peach trees, whilst the surrounding trees were 
entirely free, and remarks: “The fungus has been found on the 
unfolding shoots of a tree so early in the spring and to such 08 
extent as to make it almost certain that it had wintered over ™ 
the form of perennial mycelium. From other trees fresh-looking 
mycelium has been taken in mid-winter, and I have no doubt 
as to its perennial nature.” It was found also that ‘peach ng 
with gland-bearing leaves remained free from mildew, while mil- 
dewed trees bore leaves destitute of glands.’’ Smith remarks 
“It would seem, therefore, as though peach trees of the type 
bearing glandular leaves are more resistant to this mildew thal 
other varieties, but whether this will hold good for all localities 
and all varieties remains to be seen.” : 
Selby reports the “ peach mildew” as attacking the fruit a5 
well as injuring the leaves and twigs, and observes: “ Upon the 
fruit, this mildew causes large, light-colored spots, with 
an enor 
