Sida gathwalarum (Malvaceae), a new species from Meerut, Uttar Pradesh, India, is described and illustrated based on morphological and phylogenetic evidence. Morphologically, the new species is similar to Sida angustifolia Mill. but consistently differs from it in leaf shape, varying from narrowly lanceolate to ovate; base cuneate to rounded; petioles without spiny emergence (spur) at the base; stipules linear-lanceolate and dissimilar in shape; and yellow styles of different sizes. The species is further characterized by indehiscent fruits with the fruiting calyx soft and compressible, the corolla retuse to nearly entire at the apex, and 5(–6) markedly heteromorphic mericarps that are trigonous–globose, coarsely rugose–tuberculate, and bear a shallow U-shaped apical notch. The seeds are subtrigonous, asymmetrical, and uniformly dull brown to grayish brown. These stable diagnostic traits from different populations support its recognition as a new species, Sida gathwalarum Sumit Malik, Inam Malik & Vijai Malik, sp. nov . Molecular phylogenetic analysis of nuclear ribosomal DNA (internal transcribed spacer) sequence data of 14 Sida species supports the phylogenetic position of the new species, Sida gathwalarum , within sect. Sidae . The results of molecular phylogenetic analysis show that Sida gathwalarum is closely related to S. acuta .
Malik et al. (Mon,) studied this question.