Foliar micromorphology as a tool for identification of Indian taxa of Polygonaceae

Polygonaceae, a morphologically diverse family, cosmopolite to temperate region. In India, the family has extensive array of distribution from the coastal plains to the subtropical temperate region and almost to the subalpine regions. Polygonaceae has a very restricted flowering and fruiting period, limiting over proper identification using floral characters. This study attempts to identify the members of Indian Polygonaceae based on permanent and stable foliar morphological characters. Most of the taxa displayed microphyllous, unlobed lamina with erose margin, except Rheum nobile (macrophyllous), Polygonum runcinatum (lobed lamina). Parameters like lamina shape, shape and angle of apex and base showed significant macromorphological variations. Three different types of indumentum viz. peltate, capitate spheroidal and stellate glandular and minor venation pattern pulls significant differences. Four major stomatal types were detected viz. anisocytic, anomocytic, paracytic and pericytic, with more than one type in a single taxon. Statistical based infra generic observation identified four distinct principal component analysis (PCA) clusters separating the members of Persicaria, Polygonum, Rumex and Fagopyrum, whereas Fallopia, Rheum, Antigonon, Homalocladium were scatteredly distributed in the matrix scoring plot of PCA. Species distributional matrix of PCA was fully supported by agglomerative hierarchical clustering. The analyzed significant systematic values are quite constant at specific and/or below rank.