1886. | BOTANICAL GAZETTE. 63 
A species was found by me growing abundantly on Poa pra- 
tensis in November and again late in December mn Bessey 
calls Erysiphe communis Schl., while Trelease assigns to E. 
graminis DC. As yet only the conidial phase has been studied 
and finding of perithecia will be necessary to positively decide 
the species 
BRIEFER ARTICLES. 
Aspidium Oreopteris Swz.—The only American station 
for this species has been the Island of Unalaska, where it was discovered by Mr. 
M. Turner in 1878, but by the past season’s searches of that indefatigable 
worker, Professor Macoun, Naturalist of the Geological Survey of Canada, it is 
now located on the North American continent proper, and no less than about 
1,600 miles east of the former station. It was found August 22, 1885, on Mount 
Dawson, at thesummit of the Canada Pacific Railway pass through the Selkirk 
Range, British Columbia, a little south of lat. 51°. The patches, which were 
fairly abundant, grew on a comparatively dry slope of the mountain, at an 
altitude of 6,500 feet, or a little less, and also in wetter soil and at a greater 
altitude, « on a neighboring mountain, the upper slopes of which were covered 
by a glac 
The ae of the Canadian plants are narrower and more graceful look- 
ing, both as a whole and in all their parts, than those of the Unalaskan and 
most European forms, but Professor Eaton, to whom a specimen was sent, writes 
hithortn rv, rded 
The largest of the specimens received from Mr. Macoun has fronds 1} feet 
high, of which 33 inches forms the stalk, while the middle pinne are only 2} 
inches long. The segments, the basal ones of which are often large in propor- 
tion to those next them, are but little more than a line in width, and the under 
surface is but very slightly glandular.—T. J. W. Buraess, M. D., London, On- 
tario, Canada. 
A Cheap Camera.—A good rue for a more expensive camera-lucida 
for the microscope can be made as follow 
ut a piece of thin metal, brass or ‘sodest or even tin will do, in the form 
of a letter L. After smoothing the edges, bend one limb into an unclosed 
band, to clasp the end of the eye-piece after the cap is remo oved. Clasp the 
other limb near its juncture with the ring, with a pair of pliers, and twist it on 
its own axis through an angle of 90°. On the outer end bend a cock-eye to 
hold a piece of wood, in the end of which make a slight split and insert the 
edge of a cover-glass to serve as a mirror. Of course both the image and the 
pencil-point are seen by looking through the glass, the former by reflected and 
the latter by transmitted light. The iight reflected is sufficient to give good 
definition when ordin nary powers are used. In this way each member of a class 
an easily make a camera for himself. 
