641060 Potentilla anserina L.
- L., Sp. Pl.: 495 (1753). Lectotype (BM-000628646): Europe. Herb. Clifford: 193, Potentilla 1 (Rousi 1965: 101). - Argentina anserina (L.) Rydb., Monogr. N. Amer. Potentill.: 159 (1898).
Geography: Circumboreal-polar.
Notes: Section Anserina has its center in eastern Asia (mainly China). Only one polymorphic species or small species group reaches the Arctic. Hultén (1968a) divided the material in Alaska and the Yukon Territory on two species, Potentilla anserina and P. egedii, the latter with three subspecies and two varieties, all of which he mapped to reach the Arctic. He later transferred subsp. yukonensis from P. egedii to P. anserina. Three taxa have been recognized through times in northwestern Europe and Greenland: P. anserina and P. egedii, the latter with subsp. egedii and subsp. groenlandica. Subspecies groenlandica differs from subsp. egedii mainly in size and lower leaf surface pubescence. In addition, there is a Pacific and western Atlantic coastal plant described as subsp. pacifica or subsp. grandis, of either P. anserina or P. egedii.
The circumpolar variation pattern is rather as four taxa nearly equidistant morphologically, each separable by several characters (Elven in Ertter et al. 2011). Intermediates are found between all of them where they meet. At least the intermediates between "anserina" and "egedii" in the North Atlantic and between "pacifica" and "egedii" in the North Pacific are fertile (the other intermediates have not been investigated). Treatment as four interfertile races is merited: the coastal subsp. groenlandica (= egedii, arctic circumpolar), the coastal subsp. pacifica (= grandis, Pacific and western Atlantic), the coastal to interior subsp. anserina (Eurasia and at least eastern and interior North America), and the interior subsp. yukonensis (northwestern North America).
Subspecies anserina and subsp. groenlandica differ in several presumed independently inherited characters in leaf dissection and degree and kind of pubescence, shape and relative proportion of epicalyx segments and sepals, and dissection (or not) of sepals, and also differ ecologically. Subspecies anserina occurs on dry maritime shores and driftwalls but is equally frequent as an inland and often adventive plant on dry ground. Subspecies groenlandica is an obligate seashore plant and most often found in moist salt-marsh site types. Plants with a transitional morphology are common in intermediate site types (e.g., driftwalls) where the two taxa co-occur. There seems to be no reproductive barrier except for the eco-geographical one. There is no major ecological difference between subsp. groenlandica and subsp. pacifica (both are coastal in salt marshes) and they fully intergrade in their small meeting zone in southwestern Alaska. They differ, however, in several characters (see Rousi 1965; Elven in Ertter et al. 2011) and transitional plants are mostly easily identified. Subspecies yukonensis has partly been assigned to P. egedii but differs perhaps more from that one than from P. anserina s. str. There are three or four diagnostic characters towards subsp. anserina in hypanthium, episepals, and leaf dissection and transitional plants are not yet known, probably due to non-overlapping ranges. Subspecies yukonensis is a specialist of sandy river shores. Transitions to subsp. pacifica and subsp. groenlandica occur where the Yukon and Mackenzie rivers reach the sea.
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Source: MPF at Wikispecies
Higher Taxa
- Potentilla [6410,genus]