Recording Persicaria maculosa and P. lapathifolia (Polygonaceae)

Abstract

Persicaria maculosa Gray (Redshank) is a distinct species which can be distinguished from all forms of P. lapathifolia (L.) Delarbe (Pale Persicaria) based on the outer tepal veins. The recording and identification of these two taxa can be clouded by colour variation (especially in the latter species) and due to varied treatments in different works or Floras. This article describes ways to separate the two species and gives details of the various treatments in order for others to decide which taxonomic work should be followed. It suggests that there is a greater need for further morphological and or molecular studies for this complex group in order to form a consensus. Hybrids may occur but none have been confirmed by scientific methods. It may be that most of these taxa (especially in P. lapathifolia s.l.) are recognizable as forms or varieties, and this is also suggested (informally at present) by the author below, until further work clarifies the situation.