Ranunculus lingua L., der Zungen-Hahnenfuß

Abstract:

Greater spearwort (Ranunculus lingua L.)

Ranunculus lingua L. is a member of the buttercup family. It has petioleless, lanceolate leaves and grows in water close to the bank and reaches a height of 1.5 m. Göbel (unpublished) and SUCHANTKE (2009) have shown that in the genus Ranunculus, with its multitude of leaf forms, the respective biotopc conditions are reflected in both the plant’s habit and its leaf forms. Ranunculus lingua, and some other species of wet habitats, appear to contradict this. Their narrow, pointed leaves would lead one to expect a hot, sunny, dry habitat, because light and heat are regarded as the formative forces of pointed leaves. However, closer observation of Ranunculus lingua shows that the first leaves after germination, as well as the winter leaves that grow under water, are rounded and petioled. This gives it an openness with respect to water, which is lacking in, for example, R. gramineus, a dry grassland plant. Its leaves are narrow and pointed from the outset. The leaf venations of both these species also differ according to their habitats. The venation is networked with the aquatic plant and parallel with the dry grassland plant. Comparison of these two plants shows that despite similar shapes their typical leaves are not to be treated as equivalent and that they do indeed reflcct their habitats. By referring to various plant communities, VAHLE (2007) has presented a metamorphic series from those in areas of open water, where rounded leaf shoots sprcad out, to those with linear leaf forms in tall beds of reeds. This kind of metamorphosis is reflected by Ranunculus lingua in the change in shape of its leaves through the seasons. The relationship of Ranunculus lingua to its biotope is recognisable not in its typical lanceolate leaf, but primarily in its overall leaf metamorphosis.