Botanical Journal of the Linnean Society, 2009, 159, 343–348. With 3 figures A new multiflorous species of Leymus (Poaceae: Triticeae) from western China LIAN-BING CAI* and TONG-LIN ZHANG Northwest Plateau Institute of Biology, Chinese Academy of Sciences, Xining Qinghai 810008, China Downloaded from https://academic.oup.com/botlinnean/article/159/2/343/2418371 by guest on 02 October 2021 Received 14 June 2007; accepted for publication 11 June 2008 A new species of Leymus section Racemosus, L. pluriflorus L.B.Cai & T.L.Zhang, is described and illustrated. It grows in the eastern part of Qinghai Province and the southern part of Gansu Province, China. It most closely resembles L. crassiusculus L.B.Cai, from which it differs in having longer rachis internodes, some pedicellate spikelets, more florets per spikelet, glabrous lemmas, shorter paleas and shorter anthers. It differs from all other Chinese species taxa in Leymus with regard to the large number (8–12) of florets in its spikelets, and from all species of Leymus in adjacent countries in having three to four spikelets per node. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 343–348. ADDITIONAL KEYWORDS: Poaceae – section Racemosus L.Zhi – taxonomy – Triticeae. INTRODUCTION With the increasing number of taxa, it has become increasingly complicated to distinguish between Leymus Hochst. is a perennial genus in Triticeae that them. For that reason, in 2004, we began a revision- has a high nutritional value for livestock. It was first ary study of Leymus. We began by examining her- described by Hochstetter (1848) who included only barium sheets of Leymus from 13 (CDBI, HNWP, one species in the genus. Since then, it has become KUN, LZU, NAS, PE, SAUT, SZ, WUK, XJA, XJBI, widely accepted (for example, Pilger, 1949, 1954; XJNU, YUKU) of the main Chinese herbaria for the Tzvelev, 1960, 1976; Löve & Löve, 1961; Melderis, appropriate area. Among these specimens, we found 1980; Barkworth & Atkins, 1984; Dewey, 1984; Löve, seven puzzling samples. They had been identified 1984; Kuo & Tsui, 1987) and has expanded to approxi- as L. crassiusculus L.B.Cai, L. secalinus (Georgi) mately 50 species. Many of the most recently Tzvelev and L. ovatus (Trin.) Tzvelev in different described species are Chinese (Yen & Yang, 1983; herbaria (HNWP, LZU, PE, SAUT), but exhibited no Sun, Yen & Yang, 1992; Wu, 1992; Yang, 1994; Cai, differences in overall morphology from each other, 1995, 1997, 2000, 2001; Cui, 1996, 1998; Zhi & Cai, and were significantly different from each of the three 2006), the number recognized in the Chinese flora species in which they had been placed. In addition, having increased from nine in 1987 (Kuo & Tsui, based on existing floras and information from experts 1987) to the 24 species currently recognized (Chen & in the field, they differed from all currently recognized Zhu, 2006). In addition, two species, L. kopetdaghen- species of Leymus. This suggested that the seven sis (Roshev.) Tzvelev and L. bruneostachyus N.R.Cui specimens represented a new taxon. & D.F.Cui, were omitted from the Flora of China Because the seven specimens came from areas near (English edition), and one species, L. oblongolemma- our institution, in the autumn of 2005, we conducted tus L.Zhi & L.B.Cai, was described after its publica- field studies in the areas in which they had been tion (Zhi & Cai, 2006). Thus, there are now 27 species, collected. These confirmed that the specimens be- at least one-half of the global species, known from longed to a single species, growing mainly on moun- China, and most are found in western China. tain slopes, roadsides and margins of woodlands from 2310 to 3250 m and flowering and setting seed about *Corresponding author. E-mail: [email protected] 15 days later than the other species of Leymus in the © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 343–348 343 344 L.-B. CAI and T.-L. ZHANG Downloaded from https://academic.oup.com/botlinnean/article/159/2/343/2418371 by guest on 02 October 2021 Figure 1. Leymus pluriflorus L.B.Cai & T.L.Zhang (L. B. Cai & B. H. Ma L05, HNWP): A, plant; B, junction of sheath and blade to show ligule; C, spikelet; D, lower glume; E, upper glume; F, dorsal view of the first floret; G, ventral view of the first floret; H, anthers; I, caryopsis. Scale bar: A, 12 mm; B, C, 5 mm; D–I, 3.3 mm. region. Morphologically, the seven specimens bore Consequently, these specimens are presented here as some resemblance to L. crassiusculus, L. secalinus a new species. and L. ovatus, but differed from all three in having pedicellate spikelets, glabrous lemmas, longer lower DESCRIPTION lemmas and paleas that were markedly shorter than the lemmas. They differed from all other Chinese LEYMUS PLURIFLORUS L.B.CAI & T.L.ZHANG, species of Leymus in having 8–12 florets per spikelet, SP. NOV. (FIG.1) and from all known species of Leymus in adjacent Type: China. Qinghai Province: Xining, Xi Mts., near countries in having three to four spikelets per node. the Xining Botanical Garden, 36°36′N, 101°46′E, on © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 343–348 NEW MULTIFLOROUS SPECIES OF LEYMUS 345 mountain slopes, 2320 m, 25.viii.2005, L. B. Cai & nous, 1.5–2.5 mm long, usually premorse at the apex; B. H. Ma L02 (holotype: HNWP!; isotype: PE!). blades flat or margins involute, usually 10–28 cm long, 5–7 mm wide, occasionally uppermost blades Diagnosis: Species nova L. crassiusculo L.B.Cai less than 5 cm long, both surfaces glabrous. SPIKES proxima, a quo differt spicis sub maturitate viridulis erect, greenish in fruit, slightly crowded, 13–20 cm (non brunneolis), internodiis rhachidium plerumque long, 1.2–2.4 cm wide; rachis densely pubescent, 9–18 mm longis (non 4–10 mm), spiculis partim rachis internodes generally 9–18 mm long or some- pedunculatis et 8–12-flosculis (non omnibus sessilibus times basal ones up to 28 mm. SPIKELETS usually in et 4–7-flosculis), lemmatibus dorso glabris (non threes or fours at each node of the rachis, sessile or pubescentibus), lemmate primo 10–14 mm longo (non pedicellate at the same node, slightly compressed, 8–10 mm), paleis apice bifidis et lemmatibus vulgo 1.4–2.8 cm long (excluding pedicel), with 8–12 florets; Downloaded from https://academic.oup.com/botlinnean/article/159/2/343/2418371 by guest on 02 October 2021 evidenter brevioribus (non retusis et vulgo lemmate pedicels densely pubescent, 1–5 mm long; rachilla subaequantibus), antheris purpurascentibus et 3.5– internodes 1.0–1.5 mm long, densely puberulent; 4.0 mm longis (non flavis et c. 5 mm). glumes herbaceous, linear-lanceolate, one-nerved, glabrous on the back, sparsely ciliolate at the margins Description: Perennial herbs with rhizomes. CULMS of upper half, gradually tapering into an awn, nearly erect or slightly geniculate below, loosely caespitose equal, 11–15 mm long, 0.7–1.3 mm wide; lemmas lan- or solitary, 65–120 cm tall, 2.0–4.0 mm in diameter, ceolate, glabrous on the back, pilose along or near the three- to four-noded, glabrous or occasionally pubes- margin, distinctly five-nerved at the upper part, first cent just below the spike. LEAF SHEATHS longer or lemma 10–14 mm long, with a short awn 2–3 mm shorter than the internodes, glabrous or the lower long at the apex; callus obtuse, with 0.5–1.0 mm long sheaths sometimes pubescent, the basal sheaths per- hairs; paleas usually shorter than the lemmas by sistent, disintegrating into fibres; ligules membra- 0.5–1.5 mm, two-keeled, sparsely spinulate along the Figure 2. Distribution map of Leymus pluriflorus L.B.Cai & T.L.Zhang (filled circles) in China. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 343–348 346 L.-B. CAI and T.-L. ZHANG KEY FOR THE IDENTIFICATION OF LEYMUS PLURIFLORUS L.B.CAI & T.L.ZHANG 1. Spikelets in fours to sixes in the middle part of the spike; plants usually over 100 cm tall 1.1 Spikelets 8–12-flowered; lemmas glabrous on the back, the first lemma 10–14 mm long............................. ......................................................................................................................Leymus pluriflorus 1.2 Spikelets four- to seven-flowered; lemmas densely pubescent on the back, the first lemma 8–10 mm long..... ..................................................................................................................Leymus crassiusculus 2. Spikelets in twos or threes in the middle part of the spike; plants usually under 100 cm tall 2.1 Glumes equal to or longer than the spikelet; rachis hispid on the margins 2.1.1 Spikes 1.5–2.5 cm wide, elliptic or oblong-ovoid; spikelets divergent from the rachis, five- to seven- flowered .........................................................................................................Leymus ovatus 2.1.2 Spikes 0.4–0.7 cm wide, narrowly linear; spikelets appressed to the rachis, three- to five-flowered....... Downloaded from https://academic.oup.com/botlinnean/article/159/2/343/2418371 by guest on 02 October 2021 .......................................................................................................Leymus kopetdaghensis 2.2 Glumes distinctly shorter than the spikelet; rachis spinulate or pilose on the margins 2.2.1 Glumes lanceolate, 4–7 mm long; lemmas oblong-lanceolate, obscurely three-nerved.......................... ....................................................................................................Leymus oblongolemmatus 2.2.2 Glumes subulate-linear or lanceolate-linear, 8–15 mm long; lemmas lanceolate, five-nerved 2.2.2.1 Lemmas glabrous on the back; paleas slightly shorter than the lemma; sheaths densely pubescent................................................................................Leymus bruneostachyus 2.2.2.2 Lemmas spinulate or pubescent on the back; paleas subequal to the lemma; sheaths glabrous ......................................................................................................Leymus secalinus upper keels, glabrous between the keels, apically soils that are reddish and sandy to clayey.