The genus Tchihatchewia Boiss. and genus Horwoodia Turill have a number of common morphological characters (winged, 1‑2 seeded silicles, lilac flowers with appressed sepals, plant pubescence with bristly hairs, and erect highly branching plants) and geographic‑ecological characters (Southwest Asian arid, subarid and aridized habitats) that allow their combining into one genus Tchihatchewia Boiss., consisting of two species: T. isatidea Boiss. and T. dicksoniae (Turrill) V.I. Dorof. comb. nov.

Classifications of the genus Triticum L. differ in approaches to the number and content of both intrageneric and infraspecific taxa. According to the «GrainTax» System, an on‑line source of information on the taxonomy of wheat, there are currently 7 main classifications of the genus Triticum L. These include a classification developed at the Department of Wheat Genetic Resources of VIR, which is referred to as the “Classification of Triticum by Dorofeev et al.” This is the world’s first standardized system that contains all known infraspecific taxa of wild and cultivated wheat species. A detailed classification makes it possible to identify a wide variety of forms when working with the genus Triticum L. and its individual species, which is especially important for collections preserved in genetic seed banks. In accordance with this system, durum wheat (T. durum Desf.) is regarded as a species that includes two subspecies, 131 botanical varieties and 42 forms united into six groups and three subgroups of varieties. The basis of the infraspecific system is made up of botanical varieties with a definite complex of morphological traits of the spike and kernel. The present work contains descriptions of each botanical variety and photographs of most of them.