124 Zannichellia palustris L.

This collective species has a very wide distribution, mainly on the northern hemisphere. It occurs in saline and brackish waters along the seacoasts as well as in fresh or alkaline inland waters. Attempts at further division into lower taxa have been made. It is obviously reasonable to distinguish same taxa of specific or lower rank, at least three in N. Europe, viz. Z. major Boenn., Z. pedunculata Rchb. and Z. palustris L. subsp. repens (Boenn.) Koch (cf. Luther in Acta Bot. Fenn. 40/1947, p. 10 ff., and van Vierssen in Aquat. Bot. 12/1982, p. 107 ff. It may be toa early to make separate maps of these taxa. Together they have a circumpolar distribution (Hultén, Circumpol. I, p. 132 and map 124). The occurrence outside the area of the map is summarily noted in its margin.