The ecological, morphological, physiological, and biochemical characteristics of representatives of the genus Galium (Rubiaceae) have been studied. The objects of study are the hybrid (nothospecies) Galium × affrenum (Klokov) Ostapko (=nothospecies) and its parental species G. ruthenicum Willd., and G. octonarium (Klokov) Pobed. s. l. G. × affrenum is habitually closer to G. ruthenicum; however, it differs from the latter in pale lemon flowers. Based on the method of artificial neural networks, it is shown that the nothospecies is closer to the parental species G. octonarium with respect to physiological and biochemical features. The leaf biomass of G. × affrenum is characterized by an increased content of photosynthetic pigments and a greater variability in the concentration of photosynthetic pigments and lipid metabolism, which may be key to its greater stability and viability.