Stipa ×fallax (Poaceae: Pooideae: Stipeae), a new natural hybrid from Tajikistan, and a new combination in Stipa drobovii

Abstract

Stipa ×fallax nothosp. nov. (Poaceae), from western Pamir Alai Mts (Tajikistan), is described and illustrated. Field observation, numerical analyses of morphology, and pollen grain viability data show that it originated from hybridization between S. drobovii and S. macroglossa subsp. macroglossa, species representing sections Smirnovia and Stipa, respectively. Stipa ×fallax is morphologically close to S. ×alaica and S. ×hissarica, but is distinguished by its shortly pilose lower part of the awn and densely pubescent leaves. Characters distinguishing S. ×fallax from its parental species as well as similar hybrid taxa in section Smirnovia that also grow in Central Asia are presented. The micromorphology of lemmas and leaves of S. ×fallax and its parental species was examined by scanning electron microscopy. We also propose the new combination Stipa drobovii var. iskanderkulica (Tzvelev) M.Nobis & A.Nowak.

A Synopsis of the Genus Stipa (Poaceae) in Middle Asia, Including a Key to Species Identification, an Annotated Checklist, and Phytogeographic Analyses

“…The most important morphological characters used in the taxonomy of Stipa are presented in Figure 2. Illustrations and descriptions of other morphological characters can be found, e.g., in the work of Roshevitz (1934), Martinovský (1967Martinovský ( , 1972Martinovský ( , 1976Martinovský ( , 1977, , Moraldo (1986), Gonzalo et al (2012Gonzalo et al ( , 2013, Nobis ( , 2014, Gudkova et al (2013b), and Nobis et al ( , 2016aNobis et al ( , 2017a). MORPHOLOGICAL…”

“…Stipa drobovii var. iskanderkulica is found in Middle Asia (Ovchinnikov & Chukavina, 1957;Nobis et al, 2017a), specifically in Tajikistan (Zeravshan and Hissar Mountains). Plants perennial, densely tufted, with a few culms and numerous vegetative shoots; culms (35-)40-60 cm tall, 3-noded, glabrous at nodes and densely pubescent below them.…”

“…However, these numbers also included several taxa (based on morphological and molecular studies) currently belonging to other genera, e.g., Ptilagrostis, Achnatherum, or Stipellula. On the other hand, during the last 30 years, some new species of Stipa also have been described from central Asia by Lomonosova (1990), Kotukhov (1987Kotukhov ( , 1991Kotukhov ( , 1998aKotukhov ( , 1998b, Tzvelev (2012), Nobis ( , 2014, Nobis et al ( , 2014bNobis et al ( , 2017a, and Guo (2011, 2017). Further exploration of the region is expected to reveal additional species.…”

“…Nevertheless, before now, all information and hypotheses on the hybrid origin of these taxa, as well as on hybridization events in feather grasses, were based on morphology only. Recently Nobis et al (2019c) provided the first molecular evidence for this phenomenon in Stipa. Hybridization within this genus is particularly interesting because hybrids are perennial and reproduce vegetatively and, less frequently, sexually Nobis et al, 2017a). Most produce fertile pollen grains and therefore are, or may be, able to backcross with parental species, resulting in introgression (Nobis et al, 2019c).…”

Stipa richteriana (Poaceae) and Galium songaricum (Rubiaceae): two new additions of the Central Asian species to the flora of Iran

“…Central Asia is an important center of diversity of Stipa with ca. 70 species (Nobis et al, 2013(Nobis et al, , 2017. According to Bor (1970), in Flora Iranica, this genus is represented by 18 species in Iran.…”