The microcyclic species of Puccinia on Saxifragaceae are revised in the light of abundant recent collections. Recombinations or new varieties include: P. asiatica var. tiarellae, P. heucherae var. chrysosplenii, P. h. var. austroberingiana, P. h. var. saxifragae, P. h. var. lithophragmae, P. pazschkei var. heterisiae, P. p. var. tricuspidatae, P. p. var. huteri, P. p. var. jueliana, P. p. var. oppositifoliae. The basic species appears to be P. tottoriensis, whence three evolutionary lines have given rise to: (i) P. asiatica, P. saxifragae–ciliatae, and P. laurentiana; (ii) P. heucherae and P. pazschkei; (iii) P. fischeri and P. joerstadii. The complex originated in, probably, eastern Asia. P. heucherae vars. developed in Cordilleran North America concurrently with the development of Saxifragaceae in that region. Some varieties of P. heucherae occur on several host genera, providing clues to the comparative ages of species in these genera. Since the varieties of P. heucherae and P. pazschkei can be arranged in an evolutionary sequence, clues are available as to the relative ages of various sections of Saxifraga.