Stipa × tzveleviana Kotukhov (1994: 102)

Nobis, Marcin & Gudkova, Polina D., 2016, Taxonomic notes on feather grasses (Poaceae: Stipa) from eastern Kazakhstan with typification of seven names and one new combination, Phytotaxa 245 (1), pp. 31-42 : 37-38

17. Stipa × tzveleviana Kotukhov (1994: 102) pro sp. Type citation:—Saur-Tarbagatai, brachia australi-occidentalia jugi Manrak, 600 m s. m., locus Kempirbulak, clivulus saxosus boreali-occidentalis, 11 VII 1992, Ju. Kotuchov (LE)

Type (original label):— 11 VI 1992, Stipa tzveleviana Kotuch. (sect. Barbatae), Tip: Saur=Tarbagatai, yugo-zap. otrogi khr. Manrak, 600 m nad ur. m., urochishche Kempirbulak, sev.-zap. skalistyi mikrosklon, Typus!, Yu. Kotukhov (holotype LE!, isotypes LE! 3 sheets).

Stipa ×tzveleviana has recently been treated as synonymous with S. turkestanica Hackel (1906: 59) subsp. turkestanica by Gonzalo et al. (2013). However, our detailed examination of specimens of S. ×tzveleviana reveals that the taxon differs from S. turkestanica subsp. turkestanica in shorter ligules of vegetative shoots (2–5 vs. 2.6–11.5 mm long, respectively), a poorly developed ring of hairs present at the top of anthecium vs. top of anthecium glabrous, and in the scabrous column, which is covered by spinules or hairs (0.05–) 0.1–0.3 mm long on the lower segment and 0.2–0.5(–0.7) mm long on the upper segment vs. the lower and the upper segment of the column scabrous to glabrous ( Nobis et al. 2016).

We consider Stipa ×tzveleviana to be a hybrid, arising from hybridization of S. orientalis and S. macroglossa subsp. kazachstanica . As a hybrid, Stipa ×tzveleviana need not be phenotypically intermediate in reference to its parental species, and may have intermediate and extreme characters, as is generally typical for taxa of such origin ( Rieseberg 1995, Paszko & Nobis 2010, Nobis 2011b, 2013). For this reason, some specimens have a more or less poorly developed ring of hairs at the top of anthecium, while the same character is absent in others.

18. St i pa × zaissanica Kotukhov (1991: 873) pro sp. Type citation:— Altai Australis, brachia australi-orientalia jugi Azutau, montes Bulgartabaty, 600 m s. m., declivitas lapidosa austro-orientalis, 16 VI 1988, J. Kotuchov (LE)

Type (original label):—16. 06. [197] 88 g., Stipa sp. nov. zaissanica Kotuch. 1991 , Bot. Zhurn. 76,6: 873 [determ.] N. Tzvelev, Yuzhnyi Altai, khr. Azutau, Uroch. Bylgar-Tabaty, yugo-vostochnyi kamenistyi sklon, shchebnistye uchastki, Typus!, Kotukhov Yu. A. (holotype LE!, isotypes KRA 436028!, KRA 436029!, KUZ! 2 sheets).

In LE we found only one sheet of Stipa ×zaissanica matching the description of that species. It was determined by N. Tzvelev as S. ×zaissanica and is the holotype.

We consider Stipa ×zaissanica to be a hybrid, arising from hybridization of S. orientalis and S. hohenackeriana . Specimens of this taxon have morphological characters that are intermediate between the two parental species. The hybrid origin of S. ×zaissanica was also hypothesized by Kotukhov (1991); however, he published the taxon with the rank of a legitimate species. Original material of Stipa ×zaissanica is characterized by somewhat greater variability of main morphological characters than was presented in the protologue of the taxon. Ranges of important characters are: glumes 20–30 mm (not 20–25 mm as in the protologue) long, anthecium 9–11 mm (not 9–10 mm) long, awns 9–12 cm (not 9–11 cm) long, and hairs of awn seta 2.3–3.5 mm (not 2–2.5 mm long; see also the note under S. kamelinii ).