A type-based reassessment of Sida fryxellii (Malvaceae)

Abstract

The genus Sida L. (Malvaceae) comprises approximately 277 species distributed mainly in tropical and subtropical regions (POWO, 2026). Several species within the genus, particularly those belonging to the Sida rhombifolia complex, exhibit considerable morphological variation, leading to long-standing taxonomic difficulties and differing interpretations of species limits. In India, Sida rhombifolia has often been treated in a broad sense, with several distinct taxa reduced to synonymy or infraspecific rank (Paul,1993). Sida fryxellii was described by Sivarajan & Pradeep (1990) based on collections from coastal Kerala and was distinguished by its leaf dimorphism, dense stellate indumentum, and distinctive mericarp awns. Subsequently, Paul (1993), in Flora of India, reduced S. fryxellii to synonymy under S. rhombifolia subsp. rhombifolia var. rhombifolia, reflecting a broad species concept applied to the complex. In a later treatment, Sivarajan & Pradeep (1996) discussed S. fryxellii in detail and expressed a preference to maintain it as a distinct species, rather than a declarative taxonomic decision. Thus, his opinion was deliberately non-formal and did not explicitly reinstate the species or reject the earlier synonymy. As a result, secondary sources, including Plants of the World Online (2026) recognized S. fryxellii as an accepted species but World Flora Online (2026) considered S. fryxellii as a synonym of S. rhombifolia var. rhombifolia. Given the continued ambiguity surrounding the status of Sida fryxellii, a re-evaluation based on direct comparison of type material is necessary. The present paper aims to clarify the taxonomic status of S. fryxellii through a critical reassessment of morphological characters observable on the nomenclatural types and associated evidence.

Bangladesh J. Plant Taxon. 33(1): 145-148, 2026 (June)