What is Allium paniculatum? Establishing taxonomic and molecular phylogenetic relationships within A. sect. Codonoprasum

Abstract

Allium paniculatum L. is commonly recorded from the Euro-Mediterranean and Irano-Turanian regions. Evidence from literature and herbarium collections revealed that many different taxa of A. sect. Codonoprasum Rchb., all characterized by big size, diffuse and densely flowered umbrella, very long spathe valves, long pedicels, and cylindrical-campanulate perigon, have been wrongly attributed to this species thus affecting records on its geographic distribution and morphological characterization. In order to define the true identity of A. paniculatum, we analyzed specimens coming from the type locality (Don River), and provided details on morphology, ecology, karyology, leaf anatomy, seed morphology and seed coat micro-sculpturing. Taxonomic and phylogenetic relationships with related species of sect. Codonoprasum and with other taxa of different sections were investigated by means of morphological characters and molecular data from the internal transcribed spacers (ITS) nrDNA and the trnH-psbA cpDNA region. Maximum parsimony and Bayesian inference analyses of molecular data recovered two main clades in A. sect. Codonoprasum and clearly separated A. paniculatum from related taxa. The taxonomic implications of these patterns of relationships are discussed. To our knowledge, this is the first study documenting in-depth phylogenetic relationships within A. sect. Codonoprasum.Key words: Allium paniculatum, A. sect. Codonoprasum, karyology, morphology, phylogeny, seed coat sculpturing, taxonomy.For a long time Allium paniculatum L. has been regarded as a remarkably variable species, counting a wide range of morphologically different forms. More than thirty taxa, at specific or lower rank, were included into the A. paniculatum complex, many of which have been gradually recognized as species. The most relevant diacritic characters of this group mainly regard gross size, length of spathes, shape of inflorescence, shape and morphology of some floral traits (Levan, 1937;Wilde-Duyfjes, 1976;Stearn, 1980). Describing A. paniculatum, Linnaeus (1759, pp. 978) just provided this short protologue: "A. caule subteretifolio umbellifero, pedunc. capillaribus effusis, stamin. subulatis, spatha longissima", which was also quoted in Linnaeus (1762, pp. 428). These few diagnostic characters often caused erroneous attributions of specimens and, based on literature and herbarium surveys, several taxa of A. sect. Codonoprasum Rchb., which usually exhibit big size, many-flowered and spread inflorescences, long pedicels, very long spathe valves, and cylindrical-campanulate perigon, have been improperly referred to A. paniculatum. As a matter of fact, the name A. paniculatum has been mistakenly applied to samples of A. dentiferum Webb & Berthel., A. fuscum Waldst. & Kit., A. oleraceum L., A. pallens L., A. tenuiflorum Ten., etc. (Brullo et al., 1991(Brullo et al., , 1996(Brullo et al., , 2001(Brullo et al., , 2003(Brullo et al., , 2008a).Due to these frequent misleading interpretations, main floras and taxonomic revisions on the genus...

Intricate Distribution Patterns of Six Cytotypes of Allium oleraceum at a Continental Scale: Niche Expansion and Innovation Followed by Niche Contraction With Increasing Ploidy Level

“…This section is distributed in Northern Africa and Europe, extending to Iran and southwestern Siberia (Vvedenskii, 1935;Meusel et al, 1965;Stearn, 1980;Brullo et al, 1996a,b;Brullo et al, 2001). Allium oleraceum shows morphological similarity to species of the informal A. paniculatum complex, reaching its northern range limit in the southern parts of Europe (Stearn, 1980;Pastor and Valdés, 1983;Brullo et al, 1996aBrullo et al, , 1997Brullo et al, , 2003Dobrotchaeva et al, 1999;Ciocârlan, 2000;Jauzein and Tison, 2001;Bogdanović et al, 2008;Aedo, 2013;Tison and de Foucault, 2014;Ghendov, 2015;Salmeri et al, 2016;Brullo and Guarino, 2017), and characterized by plants with ribbed and glabrous leaves with a semicylindrical to flat outline, spathe valves with a long appendage, and a campanulate perigon with stamens included or just slightly exerted (Brullo et al, 1996a(Brullo et al, ,b, 2001(Brullo et al, , 2003(Brullo et al, , 2008Salmeri et al, 2016). The origin of A. oleraceum is still puzzling; nevertheless, an alloploid origin is the most probable (Levan, 1937;Vosa, 1976;Duchoslav et al, 2010).…”

Allium albanicum (Amaryllidaceae), a new species from Balkans and its relationships with A. meteoricum Heldr. & Hausskn. ex Halácsy

“…As emphasised by numerous authors (Pastor 1981, Češmedžiev and Terzijski 1997, Fritsch et al 2006a, Neshati and Fritsch 2009, Celep et al 2012, Salmeri et al 2016, Lin and Tan 2017, Özhatay et al 2018, Brullo et al 2018), the micro-sculptures of the seed testa in the Allium species represent a very stable and conservative character, showing usually relevant taxonomical and phylogenetical implications. Seeds of A.albanicum at low magnification (30×) showed a semi-ovoid shape (3.5–4.0 × 2.4–2.5 mm), with a rather rugose surface (Fig.…”

Table_2.XLS

“…hexaploids) or allopatrically (tri-vs. hepta-and octoploids; Figure 1). The current distribution of all cytotypes also overlaps the range of diploid, sexually reproducing hypothetical progenitors of the A. paniculatum complex (Stearn, 1980;Pastor and Valdés, 1983;Brullo et al, 1996a;Salmeri et al, 2016), but exclusively at lower latitudes. Considering both polyploid A. oleraceum and diploids of A. paniculatum complex, most regions with a high cytotype diversity are confined to unglaciated areas during the LGM while only polyploids are currently distributed at both higher latitudes and elevations, with tetraand pentaploids being the only cytotypes represented in northern areas which were glaciated during the LGM (Huntley and Birks, 1983).…”

“…& Kit. ; Levan, 1937) however share two characteristics: (i) their niches are restricted to a narrow range of natural habitats (rocky outcrops and dry grasslands) in (ii) dry and warm regions of southeastern Europe (Stearn, 1980;Brullo et al, 1996aBrullo et al, , 2001Dobrotchaeva et al, 1999;Ciocârlan, 2000;Ghendov, 2015;Salmeri et al, 2016). In contrast, the niche of polyploid A. oleraceum also comprises more mesic (colder and moister) climatic conditions (Figures 1-3) and a wide spectrum of habitat types, including fertile weedy habitats (Figure 4).…”