Abstract:

The genus Stipa in the Altai territory is represented by 12 species (Lomonosova, 2003, Silanteva, 2013, Gudkova et al., 2015). Stipacapillata L., which belongs to the Leiostipa Dumor. section, is one of the most widespread species of this genus. Besides S. capillata, two more species of this section – S. praecapillata Alech. and S. Baicalensis Roshev. occur on the territory of the region. However, they both have a very limited distribution: the first is represented by single finds in Klyuchevsky, Kuryinsky, Pospelikhinsky and Rubtsovsky districts of Altay, and the latter one occurs only in Charyshsky district. Thus, in the territory of the region there is a unique opportunity to study the population variability of S. capillata, as in other regions it often grows together with closely related species and hybridizes with them (in the west with S. sareptana A. Beck., and S. praecapillata Alech., and in the south and east - with S. grandis P. Smirn, S. krylovii Roshev and S. baicalensis. The problem of the volume and boundaries of S. capillata L. is caused by its wide distribution from Spain to Yakutia and high polymorphism. Many authors accepted the different limits of variability in the characteristics of S. capillata, which makes it difficult to define this taxon, for instance, in almost all the floristic revisions the authors suggest, that the node of generative shoot is hidden by the leaf sheathes because of the leaf sheath is longer than the internode, and only N.N. Tsvelev (Tzvelev, 1976) and H. Freitag (Freitag, 1985) admit that a node within this species can be exposed. The purpose of our study was to research the population variability of S. capillata on the territory of the Altai in order to specify the limits of its features variation. 242 individuals of S. capillata belonging to 11 populations were involved in the analysis. The paper presents the result of statistical analysis by 26 quantitative and 2 qualitative features. A description of the lemma ultrastructure is also given. On the basis of the analysis, a refined morphological description of the species is given and the limits of variability of characteristics are indicated. It has also been established that some individuals with trichomes up to 0.15 mm on the tip of lemma, as well as individuals with closed nodes can be found within S. capillata species. It rejects the morphological pattern, accepted for S. capillata earlier. Despite the significant broadening of the boundaries of the variability of the signs, morphological differentiation was not revealed. All objects included in the analysis form a single cluster and belong to one general population. Also, the article provides information on the ecologo-cenotic association and distribution of this species based on the revision of herbarium collections stored in AA, BM, E, GAT, K, KAS, KRA, KUZ, LE, M, MW, MHA, TK, NS, NSK, UPS.

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