Biosystematics of Hordeum

Hordeum is a more complex genus. From the current study of genetic biosystematics, there are 32 species in Hordeum. However, it is genetically related to four independent groups. Although they are very similar in morphology, each has its own distinct set of chromosomes. From the point of view of biosystematics, it is reasonable to divide them into four genera. However, Áskell Löve (1982, 1984) once divided it into two genera, namely Hordeum and Critesion. But due to historical limitations, there were two separate sets of chromosomes in Critesion that had not been discovered at that time. Under his principle that “a genome or a combination of chromosomes constitute a genus,” the Critesion should also be separated into two new subgenera. They are similar in morphology and are difficult to distinguish, and the population number is not too much. Traditionally, to be easy to use, we still combine them into a genus, but they belong to four groups based on genetic systematic analysis. All supraspecific taxonomy is artificial, which is the objective reality that the author of this book explains repeatedly to the reader.