Betula
This genus comprises about twenty-five species, broadly dispersed over Europe, Central and North Asia, and North America. To those described on p. 186, Vol. I., the following should now be added:
B. Medwediewi (Medwediew's). fl., catkins cylindrical, the males about 1 1/4in. long, the females shorter. l. elliptic-ovate, acutely toothed, glabrous, the midrib beneath and the petiole pubescent. Branches glabrous. Transcaucasus, 1887. (R. G. 1887, p. 384, f. 1-4.) B. Raddeana (Radde's). fl., catkins ovoid-oblong, 3/4in. to 1in. long. l. small, ovate, acutely toothed, pubescent beneath on the nerves and in the angles of the nerves. Young shoots softly pubescent. Caucasus, 1887. (R. G. 1887, p. 384, f. 5-11.)