Vallisneria densiserrulata

The name Vallisneria densiserrulata is hardly known in the aquarium hobby. This species is probably cultivated as an aquarium plant but is mistaken for Vallisneria spiralis. Plants imported from Malaysia under the label "V. spiralis" were identified as V. densiserrulata by DNA analysis.

This Vallisneria was described in 1914 by the Japanese Makino as a variety of V. spiralis (V. spiralis var. densiserrulata) and was later established as a separate species. The original spelling is "denseserrulata", but "densiserrulata" is apparently grammatically correct. Lowden (1982) regards this vallisneria as a V. spiralis variety, whereas Les & al. (2008) in turn treat it as a species.

According to the "Flora of China", Vallisneria densiserrulata occurs in southern and eastern China and in Japan and colonises streams and lakes.

This species looks very similar to V. spiralis. As in other vallisnerias, the leaf margin is densely set with small teeth, but in addition V. densiserrulata also has tiny teeth on the leaf midrib. It shares this feature with the species Vallisneria spinulosa, which also occurs in China.