A small tree of the balsam group, with downy, terete shoots. Leaves triangular-ovate, acute at the apex, rounded to slightly cordate at the base, about 4 in. long, 2 in. wide, dark green above, downy on the midrib and main veins and whitish beneath, margins ciliate, finely crenate; petioles downy. Flowers and fruits not seen.
P. tristis was described by Fischer in 1841 from a tree cultivated at St Petersburg (Leningrad) where it is said to be still grown as an ornamental, and to be so hardy that it is able to survive the winters of Murmansk and Verkhoyansk, north of the Arctic Circle (Arb. Kornickie, Ybk. IV (1959), pp. 132-3). It is not recognised as a species in the Flora of the Soviet Union, nor have matching plants been found in the wild (Elwes and Henry suggested that it might be the same as a poplar found wild at high elevations in the N.W. Himalaya, but Schneider disagreed). Except in the shape of its leaves and its small size, it bears some resemblance to P. candicans, another poplar of uncertain origin.
A tree considered to be the true P. tristis was introduced to Kew from Späth’s nursery in 1896, but it did not thrive; although it made vigorous growths during the summer, they were frequently cut back during the winter, and it never got beyond a few feet high.