56 THIRTIETH REPORT ON THE STATE MUSEUM. 
CERCOSPORA CHENOPODIL ck. 
Living leaves of Chenopodium album. West Albany. July. 
PERONOSPORA ALTA F'ckl. 
Living leaves of plantain, Plantago major. Albany. July. 
This is sometimes regarded as a form of P. effusa. 
PERONOSPORA INFESTANS De By. 
Living leaves of potato vines. Adirondack. August. 
This fungus, for a long time considered the cause of the 
potato disease, has, until recently, baffled all efforts to trace 
its life-history. But at last Mr. W. G. Smith, an earnest 
botanist, a most careful observer and skillful experimenter, 
has succeeded in tracing this history through the yearly cycle. 
He has found and kept alive through the winter, the hiber- 
nating or resting spores of the fungus and caused these to 
reproduce the pestilent potato fungus. His discovery is so 
important that 1 cannot do better than to quote his concluding 
remarks on the subject, a full account of which is given in the 
Gardeners’ Chronicle: 
‘‘For more than thirty years our potato crops have been 
systematically destroyed by two virulent fungi, viz., Peronos- 
pora infestans and Fusisporium Solani; these two parasites 
almost invariably work in company with each other, they 
suddenly appear for a few weeks, destroy our crops and vanish 
for ten or twelve months then reappear and repeat the work of 
destruction. I claim for my work that it is new, and that it 
has proved how both these fungi hide and sleep through eleven 
months of the year. As I have kept the resting-spores of both 
parasites alive artificially in decayed potato leaves in water, in 
moist air, and in expressed diluted juice of horse dung, it con- 
clusively proves to me that the resting-spores hibernate natur- 
ally in the same manner. The seat of danger from both para- 
oe is clearly in dung heaps, ditch sides and decaying potato 
plants. 
‘‘Any method of destroying the resting-spores of these pests, 
or of warding off or mitigating their attacks, obviously depends 
in a great measure upon a full knowledge of their life-history. 
That life-history 1 have endeavored, to the best of my ability, 
to watch and describe for the Gardeners’ Chronicle, and I am 
content to let the observations stand on their own merits. 
Sensibly conducted and extensive field experiments might 
probably teach some valuable lessons, but it 1s difficult, if not 
impossible, for any single individual, whether farmer or botan- 
ist, to institute and carry out such experiments.”’ 
VERTICILLIUM PULVEREUM P. & C. n. sp. 
Effused, pulverent, dark or snuff-brown ; flocci colored, the 
lower branches alternate, the upper opposite or verticillate, 
