Taxonomic Status of Some of the Tribulus Species in the Indian Subcontinent

Tribulus L. is considered as the most complex genus in Zygophyllaceae because of enormous number of invalid specific epithets and also of the variations present in various populations. A comparative study has been carried out on specimens of a number of species in the Arabian Peninsula and India to find out whether the species with identical characters reported from above regions are indeed same or different. Distribution range of a few species reported from India has also been extended in the light of the present study. Nomenclature status of certain species’ names widely used in India, such as T. lanuginosus L. and T. longipetalus Viv have been verified, while the subspecies status of T. lanuginosus ssp. macropterus (Boiss.) Maire ex Ozenda & Quezel has been elevated to species level. The reasons explained by other authors for lowering the species status of T. rajasthanensis Bhandari & Sharma to a variety level; and a detailed comparative study on T. subramanyamii P. Singh, Giri et V. Singh with similar species reported from West Asia are included in the text. A provisional key to the species of Tribulus in India is also provided for easy determinations.