Natural History Sciences. Atti Soc. it. Sci. nat. Museo civ. Stor. nat. Milano, 5 (2): 57-64, 2018 DOI: 10.4081/nhs.2018.392 A survey of the Elymus L. s. l. species complex (Triticeae, Poaceae) in Italy: taxa and nothotaxa, new combinations and identification key Enrico Banfi Abstract - Elymus s. l. is a critical topic on which only a little INTRODUCTION light has begun to be made regarding phylogenetic reticulation, Elymus L. s. l. is one of the most debated topic among genome evolution and consistency of genera. In Italy, Elymus s. l. officially includes ten species (nine native, one alien) and some genera within the tribe Triticeae (Poaceae), with represen- well-established and widespread hybrids generally not treated as tatives spread all over the world. It has been the subject little or nothing is known of them. In this paper fourteen species of basic studies (Löve A., 1984; Dewey, 1984) that have (with two subspecies) and six hybrids are taken into account and opened important horizons not only in the field of agroge- the following seven new combinations are proposed: Thinopyrum netic research, but also and especially on systematics and acutum (DC.) Banfi, Thinopyrum corsicum (Hack.) Banfi, Thi- taxonomy. However, the still rather coarse knowledge of nopyrum intermedium (Host) Barkworth & Dewey subsp. pouzolzii (Godr.) Banfi, Thinopyrum obtusiflorum (DC.) Banfi, Thinopyrum the genomes and the lack of a satisfactory interpretation ×duvalii (Loret) Banfi, ×Thinoelymus drucei (Stace) Banfi, ×Thi- of their role in the highly reticulate phylogeny of Triticeae noelymus mucronatus (Opiz) Banfi. Some observations are pro- for a long time discouraged taxonomists to clarify species vided for each subject and a key to species, subspecies and hybrids relationships within Elymus s. l., trying to circumscribe is made available. genera consistent on genetic and morphological basis. Key words: combinations, Elymus, Elytrigia, hybrids, Italy, Subsequently many researchers supported by phylogene- key, nomenclature, taxonomy, Thinopyrum, ×Thinoelymus. tic investigation have solved problems of genome identi- ty succeeding in a more and more better clarification of intergenomial affinities and confirming more and more Riassunto - I recenti progressi della filogenesi in campo geno- reliably the genome donors (see for example Chen et al., miale hanno consentito di riproporre la delimitazione di alcuni generi più o meno sommersi in Elymus s. l. In Italia ad Elymus s. 1998; Dızkirici et al., 2010; Fan et al., 2013; Mason- l. sono ascritte ufficialmente dieci specie (nove autoctone e una Gamer, 2013; Dong et al., 2015; Gao et al., 2016). For alloctona) oltre ad alcuni ibridi stabilizzati e ben diffusi, ma poco taxonomic purposes, some correlations between genetic considerati in quanto mal conosciuti. In questa sede sono prese in arrangement (expressible through genomial formulas) considerazione quattordici specie (con due sottospecie) e sei ibridi, and morphology, ecology and phytogeography have gra- inoltre vengono proposte le seguenti sette nuove combinazioni: dually been highlited although much remains to be done. Thinopyrum acutum (DC.) Banfi, Thinopyrum corsicum (Hack.) Banfi, Thinopyrum intermedium (Host) Barkworth & Dewey subsp. The synthesis of current knowledge is summarized in the pouzolzii (Godr.) Banfi, Thinopyrum obtusiflorum (DC.) Banfi, taxonomic model adopted by Soreng et al. (2017), where Thinopyrum ×duvalii (Loret) Banfi, ×Thinoelymus drucei (Stace) Elymus s. l. is resolved into five genera [in the haplome Banfi, ×Thinoelymus mucronatus (Opiz) Banfi. Ad ogni entità acronym, P stands for Agropyron Gaertn., H for Hordeum trattata sono affiancate delle osservazioni e infine si fornisce una L. sect. Stenostachys Nevski, Y possibly for Peridic- chiave per la determinazione di specie, sottospecie e ibridi. tyon sanctum (Janka) Seberg and W for Australopyrum Parole chiave: chiave, combinazioni, Elymus, Elytrigia, ibridi, (Tzvelev) Á.Löve.]: Douglasdeweya C.Yen, J.L.Yang & Italia, nomenclatura, tassonomia, Thinopyrum, ×Thinoelymus. B.R.Baum (haplome: StP), Elymus L. [LT: E. sibiricus L.] (= Campeiostachys Drobow, Elytrigia Desv., Hystrix Mo- ench, Roegneria K.Koch, Sitanion Raf.; haplomes: StH, StStH, StHY, StY), Kengyilia C.Yen & J.L.Yang (haplo- me: StYP), Pseudoroegneria (Nevski) Á.Löve (haplome: St) and Thinopyrum Á.Löve (haplome: J). On this basis, Sezione di Botanica, Museo di Storia Naturale di Milano, Corso the European Elymus s. l. (Melderis, 1980) consists of th- Venezia 55, 20121 Milano, Italia. ree genera, Elymus s. s., Pseudoroegneria and Thinopy- E-mail: [email protected] rum, among which Elymus and Thinopyrum are represen- ted in Italy. © 2018 Enrico Banfi The knowledge of Elymus s. l. in Italy remained sub- Received: 29 January 2018 stantially the same for a long time, starting from Fiori Accepted for publication: 5 September 2018 (1923), who reported sub “Agropyrum” six species (incl. Agropyron cristatum (L.) Gaertn. subsp. pectinatum 58 ENRICO BANFI (M.Bieb.) Tzvelev = A. pectiniforme Roem. & Schult.), in relation to the development of pre- and post-anthetic fourteen varieties and two hybrids. Pignatti (1982), anthers, the quantity and quality of the pollen and the adopting again Agropyron, considered a total of ten spe- presence of normally developed caryopses in late season cies and two hybrids; finally Pignatti (2017), recovering collected specimens. Furthermore, the morphology of the Elymus and keeping apart A. pectiniforme, takes into ac- leaf adaxial surface was taken into account, especially re- count nine species, three subspecies and four hybrids. garding the kind of ribs (thickness and profile), their suc- The current treatment is reported in the checklist of the cession from margin to margin on blade surface and the Italian flora (Bartolucciet al., 2018; Galasso et al., 2018). presence of trichomes such as spinules, short hairs, long No doubt, the major troubles in systematics and taxono- hairs. Cilia and spinules have also been checked on the my of Italian Elymus are derived largely from the strong edges of the rachis and rachilla segments as well as on diversity of Elymus repens and its gene flow relation- margins and keels of glumes, lemmas and paleas together ships with Thinopyrum species, still overall difficult to with free margins and surface of the sheath. A particular interpret and so far only partially resolved. In this regard, kind of spinules called papillae, provided with a bulbous the most influenced morphological characters are the base with an aculeate apex facing forward (antrorse) re- glaucescence, the profile, thickness and sequence of ribs calling the sting of a scorpion, has been investigated on on the adaxial blade surface, the morphology of glumes the adaxial, concave surface of the glumes as an important and lemmas and the hairiness. Hohla & Scholz (2011) diagnostic character. Finally, dimensional characters of have investigated some Austrian Elytrigia populations the synflorescence, spikelet and flower, together with fea- concluding with the description of two species, Elytrigia tures of the vegetative shoots, culm bases and rhizomes, aeneana and E. laxula, recognized by these authors as have also been taken into consideration. separated from the sympatric Elytrigia repens (= Ely- mus repens) and E. atherica (= Thinopyrum acutum, see below) and believed to be endemic to Austria. Unfortu- TAXA AND NOTHOTAXA TREATED, NEW nately, nothing is known about ploidy level and genome, COMBINATIONS however, because of pollen sterility documented by the According to the checklist of both native and alien same authors, E. aeneana and E. laxula are likely to fall Italian flora (Bartolucci et al., 2018; Galasso et al. 2018), into the hybrid complex of Elymus campestris, E. repens Elymus s. l. (excl. Agropyron) in Italy is represented by and Thinopyrum acutum, shared by most of the popula- ten species, nine of which native and one alien (E. ob- tions from Europe, including Italy. Such phenotypes, for tusiflorus); there are three subspecies, one of which (E. example, can be observed in France (Tison & de Fou- hispidus subsp. pouzolzii) is indicated as possibly present, cault, 2014), where thrive both Elymus campestris subsp. but until now not confirmed. The Italian (regional) distri- campestris and E. c. subsp. maritimus (Tzvelev) Lambi- bution for each taxon is reported with further information non, the first one known as the parental of hybrids with in the aforementioned checklists. In the present treatment, Elymus repens and Thinopyrum intermedium. In Italy E. six species, that for some reasons concern the Italian flo- campestris subsp. campestris was erroneously reported ra, have also been taken into account. Furthermore I have by Fiori (1923) as a synonym of Agropyron repens (L.) considered three nothotaxa and three unnamed hybrids, P.Beauv. var. arenosum (Spenner) Fiori (≡ Elymus areno- both actually and potentially widespread in Italy, which sus (Spenner) Conert), generating a double issue since are poorly known, possibly confused with the parental 1) the synonymy is mistaken, 2) the distributional area species and only marginally mentioned in the floras. I did of E. arenosus is limited to northern Atlantic Europe. not take into consideration the genus Agropyron since it Nevertheless, as we will see later, there are concrete in- appears sufficiently separated from Elymus s.l., to which dications of the occurrence of Elymus campestris in Italy is related only as genome donor. and at