Morphological characteristics of a rare endemic species, Erysimum croceum M. Pop. (Brassicaceae) from Trans-Ili Alatau, Kazakhstan

Erysimum croceum is a rare endemic species listed in the Red Book of Kazakhstan. In 2015–2017 we studied three populations of this species on the territory of the Ile-Alatau National Park (Trans-Ili Alatau, Northern Tian-Shan). As a result of the inventory of sampling plots, we estimated the elevation range occupied by the species and identified age structure and population density. Our results confirmed earlier reports of low population counts of E. croceum. We also studied biometric characteristics of virginal and generative individuals of E. croceum from different populations, and measured parameters of their seeds. The morphometric parameters were highly variable across the studied populations. The only exception was the morphometric parameters of the seeds, which had low or very low variability. We conclude that these parameters are the most stable characteristics of the species. The results of the study can contribute to our understanding of population structure and dynamics of E. croceum and assist in developing effective conservation strategies for this species.