Lapland, Norway, or Norwegian, [5], [71], [72], [74], [75], [80], [87], [97], [103], [105], [112]

Siberian, [74], [75], [77]

Richardson, Sir John, [5], [7]-[9], [44], [46], [69], [103]

Rita, [6], [34] (fig.), [35] (fig.), [56] (fig.)

Ross, Bernard R., [46]

Russell, Frank, [112]

[Sabrosky], C. W., [73]

Salix planifolia, [98]

Schweder,

Charles, [6], [12], [13], [17]-[19], [27]-[29], [31], [32], [37], [44], [45], [48]-[51], [56] (fig.), [58], [59], [62]-[64], [66], [68], [69], [71], [73], [79]-[81], [83], [85], [86], [88], [95], [97]-[108], [111]-[114]