1530 Polemonium caeruleum L.

This mainly boreal species is included in a complex with some more or less critical taxa. It occurs in N., C. and E. Europe and in Asia, especially in the mountains. It is cultivated in gardens in most of Europe, from which it easily escapes. Often native and escaped specimens are mixed together. Thus it is almost impossible to draw the limits of the original distribution area. The species has also been introduced into eastern N. America. P. caucasicum N. Busch and P. himalayanum Baker are distinguished in Caucasus and the C. Asiatic mountains and in the Himalayas, respectively. A closely related species, P. van-bruntiae Britt., occurs in eastern N. America. The whole P. caeruleum complex has a circumpolar distribution, although with a large gap in E. Asia and N. America (Hultén, Circumpol. II, p. 82, 336 f. and map 74). The closely related species, reported on map no. 1531, almost fills out that gap. Cf. also Meusel et al. 1978, map p. 360.