Isoetes × atruensis hyb. nov. is shown to be a triploid (2 n = 3× = 33 + 1) sterile interspecific hybrid between diploid (2 n = 2× = 22 + 1) I. coromandelina and tetraploid (2 n = 4× = 44 + 1) I. rajasthanensis . It has been found in two locations in Rajasthan, India. It is a perennial, shallow‐water aquatic best distinguished by a set of morphological characteristics and a ploidy level that is intermediate between its putative parents. Isoetes × atruensis is the second Isoetes hybrid taxon reported from the Indian subcontinent and the first to be confirmed from multiple locations on the subcontinent.
Singh et al. (2026) studied this question.