Panarctic Flora

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630627 Oxytropis sordida (Willd.) Pers.

Geography: European (N) - Asian (N).

Notes: Astragalus sordidus was described from Scotland and the northernmost Norwegian province of Finnmark. The names Oxytropis campestris subsp. sordida and O. sordida have subsequently been applied to Nordic and Russian plants, not to the Scottish ones which currently are regarded either as O. campestris subsp. scotica Jalas (e.g., Elven et al. 2005) or included in O. campestris s. str. A lectotype of the name Astragalus sordidus should be selected (if not already done) among northeastern Norwegian (Finnmark) material to confirm the current and long established usage.

Northern European Oxytropis sordida does not conform very well to Yurtsev's distinction between red/blue and white-flowered lineages. Plants with sordid white to pale yellow flowers occur quite regularly together with sordid pale blue, lilac, or nicely purple flowers in northeastern Norwegian populations, i.e., in the assumed type area. There is a continuous series in flower colour and no reason to assume that there are two taxa in that area.

Oxytropis sordida as circumscribed by Yurtsev is the most widely distributed part of the O. campestris group. According to Hultén and Fries (1986) and Yurtsev (1986), it occurs more or less continuously from northeastern Norway and Finland east to Taimyr. In addition, Yurtsev included two disjunct population groups farther east, in Yakutia and the northern Russian Far East, as two subspecies. We here confidently exclude the Alaskan var. barnebyana from O. sordida (see O. arctica above) and are also skeptical to whether the two other races proposed by Yurtsev belong close to O. sordida.

In all current European treatments, O. sordida is regarded to be a northeastern subspecies of European O. campestris. Oxytropis campestris is widespread as a major subsp. campestris in Europe but many population groups have been described as (local) subspecies. The main argument for O. sordida as a subspecies of O. campestris is the morphological intermediates reported from, e.g., southern Finland. However, Hämet-Ahti et al. (1998) included all Finnish plants in subsp. sordida and the intermediates may be non-existing. Both European O. campestris s. str. and O. sordida are hexaploids, whereas the Asian races proposed by Yurtsev within his concept of O. sordida are dodecaploids. Yurtsev commented: "The difference between the situation in western Eurasia and Mega-Beringia can be easily explained in terms of extensive glaciation in western Eurasia and the existence of extentive non-glaciated areas east of Taymyr. As a sequence, deglaciation in the west opened the possibility to populate free lands continuously, whereas flooding of the shelf in the east against the background of Holocene expansion of Hypoarctic tundra vegetation was a challenge for the true arctic shelf vegetation". We do not see how this argument is relevant to this question. An alternative viewpoint could be that the progenitors of the hexaploids O. campestris s. str. and O. sordida survived at least the last glaciation, respectivelly, south and northeast of the northern European Ice Shield, differentiated into the present-day taxa in isolation, but merged again due to insufficient reproductive isolation on secondary contact during re-invasion in northeastern Europe, if transitional forms are proved. However, transitions between O. sordida and O. campestris remain to be documented.

The two dodecaploids in Asia proposed by Yurtsev as races of O. sordida - subsp. arctolenensis and subsp. schamurinii, and probably also O. beringensis - could have a different history and phylogeny where O. sordida either is only a part, or (more probably) not at all a part, of the origin. We retain the two first-mentioned as subspecies of O. sordida mainly because there are no nomenclatural alternatives available.

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