" A. M.," Pittsburg, Pa., says : "Referring to the letter of 'W. D. K.,' in your November number, permit me to add that I found magnificent specimens of the White (sometimes called Blue) Spruce on the slopes of Long's Peak, Col., at an elevation of eight thousand feet, and smaller trees of the same variety, to the exclusion of all other evergreens, all the way from there up to the ' timber line,' say ten thousand to eleven thousand feet elevations above the sea level. Lower down there was a fair mixture of Balsam Fir."

[This note is an illustration of the confusion arising from the indiscriminate use of common names. The "white" or " blue" spruce of Long's Peak at the lower elevations is Abies pungens - the higher ones chiefly A. Englemanni - the "Balsam" Fir, Abies concolor. The one referred to in the November number is, we took to be, the original white spruce, Abies alba, but which, as Dr. Gray corrects in the present number, should have properly been credited to the black spruce. - Ed. G. M.]