Taxonomic notes on persicaria lapathifolia (Polygonaceae/ Polygonoideae) focusing on Türkiye

Abstract

Persicaria lapathifolia has exhibited significant variation in its external morphological characteristics (e.g., stem dotting, leaf shape, leaf and ocrea indumentum, perianth properties), leading to different classifications by many taxonomists. According to recent records, P. lapathifolia is represented by P. lapathifolia subsp. brittingeri, P. lapathifolia subsp. lapathifolia, and P. lapathifolia subsp. nodosa in Türkiye. In the present study, P. lapathifolia is evaluated, focusing on morphological and molecular evidence (internal transcribed spacer sequences) inferred from extensive examination of both authentic herbarium specimens (from national and international collections) and newly gathered field samples. Morphological observations revealed that members belonging to Turkish subspecies exhibited very similar characteristics that do not provide sufficiently diagnostic features to describe the infraspecific variation of P. lapathifolia. Also, phylogenetic analyses further support the morphological similarities, confirming the lack of clear genetic differentiation among the members of Turkish specimens. When the specimens belonging to subsp. brittingeri and subsp. nodosa collected from Türkiye were examined in detail, and it was determined that they clearly belong to subsp. lapathifolia. This morphological similarity is also highly supported by phylogenetic analyses based on internal transcribed spacer data. All these findings show that P. lapathifolia is represented by P. lapathifolia subsp. lapathifolia in Türkiye. Therefore, the extended description, chorology, and phylogenetic relationships of the P. lapathifolia subsp. lapathifolia are presented in detail for the first time in the present article.