Panarctic Flora

580241-43 The Salix lanata aggregate S. calcicola, S. lanata, S. richardsonii

Geography: Circumpolar.

Notes: Argus, Skvortsov, and Elven: Argus and Elven (PAF proposal) argued for recognition of three species in a Salix lanata aggregate. Hultén (1968a) treated them as three subspecies, Skvortsov (1968, 1999) treated the two taxa present in Russia as two subspecies, and Argus (1973) was prepared to accepted them as subspecies. Skvortsov (in comments) thought that some provisional (conventional) agreement is needed regarding this group; the best would be three subspecies but three species might also be acceptable. Subsequent study (Argus unpublished) of S. richardsonii and S. calcicola in arctic Canada showed that their area of overlap is only on Southampton Island and central Baffin Island, and that evidence of hybridization there is lacking. No reasons for giving them racial rank have been given except that they form a circumpolar series of morphologically similar taxa. Salix calcicola resembles Icelandic S. lanata but differs in its much less hairy leaves (and then with straight hairs only), stipules obtuse to rounded (not acuminate), floral bracts with white hairs (never yellow), and generally shorter catkins. Also the occurrence of yellow inner bark, characteristic of S. lanata, has not been reported for either S. richardsonii or S. calcicola. Salix richardsonii differs from S. calcicola, e.g., in its narrower leaves, very prominent lanceolate stipules, and long petioles. Salix richardsonii is reported to overlap S. lanata "to the Lena or to the Khatanga" (Skvortsov 1968, 1999). In way of separation Skvortsov mentioned the absence of yellow floral bract hairs in S. richardsonii and its small, less toothed, and weakly hairy leaves. The note on dentate leaf margin is intriguing as Scandinavian (and type) S. lanata has entire leaves. We accept the taxa as three species and a fourth is provisionally entered as a race of S. lanata.