1890.] Mineralogy and Petrography. 75 
axial interference figure with an optical angle of 3°—4°, while in the 
exterior zone the axial angle is 30°-35°. In both substances the axial 
figure is decreased by heating. Their hardness is above .7, and their 
specific gravity, 3.331. Their conductivity for heat is greatest in the 
direction of the ¢ axis.—— Three new cufro-descloizites are described 
and analyzed by Hillebrand.*! The first occurs massive in the May- 
flower Mine, Beaverhead county, Montana, in lumps of a dull yellow to 
pale orange color. The second is found as thick botryoidal incrusta- 
tions in quartz, with a dull green color on the surface, and a brown 
color on a fresh fracture. It is found at the Lucky Cuss Mine, Tomb- 
stone, Arizona. The third came from the Commercial Mine, George- 
town, New Mexico, where it also is found as an incrustation on guar#s, 
It varies in color from yellow through all shades of orange red to 
` deep reddish-brown. The incrustations are distinctly crystalline, be- 
ing made up of globular masses composed of little flat crystals 
crowded close together. At other times the incrustation is acicular in 
shape, when it appears to have formed on bunches of radiating 
mite needles. The composition of this variety is: 
PbO CuO FeO ZnO V,O, As,O, EO, H,O Cl SiO, CaO sA 
§6.0% 1.05 .07 17.73 20.44 .94 +26 2.45 -04:1.0r .04 
BOTANY. 
Uredinial Parasites.—From a practical standpoint as well as 
from a biological, uredinial parasites are exceedingly interesting. A 
specimen, or specimens rather, found in Dawes County, Nebraska, this 
summer (July 20), deserve, I think, special mention. An A®cidium 
on Lygodesmia juncea Don. (Æcidium compositarum Mart. var. lygo- 
desmize Webber), was found very commonly. It was very destructive, 
frequently distorting whole plants, and, by partially stopping the 
growth above, giving them a somewhat depressed much branched ap- 
pearance. 
The avenger, however, was close at hand, entirely too close for the 
good of the 4icidium. Not in the form of man, with his multifarious 
external poison applications, but simply another little parasite on this 
parasite, wreaking vengence. It was the little Zudserculina persicina 
(Ditm.) Sacc., a plant closely allied to the smuts, found very rarely in 
21 Amer. Jour. Sci., June, 1889, p. 434. 
