Biosystematic Studies on the Genus Ixeris and its Allied Title Genera (Comp o sitae-Lactuceae) (IV) : Taxonomic Treatments and Nomenclature Author(s) Pak, Jae-Hong; Kawano, Shoichi Memoirs of the Faculty of Science, Kyoto University. Series of Citation biology. New series (1992), 15(1-2): 29-61 Issue Date 1992-12 URL http://hdl.handle.net/2433/258921 Right Type Departmental Bulletin Paper Textversion publisher Kyoto University Mem. Fac. Sci. Kyoto Uniy. (Ser. BioLl, 15: 29-61, Dec., 1992 Biesystematic Studies on the Genus Ixeris aRd its Allied Geilera (Cempositae-Lactuceae) IV. Taxonemic Treatments and Nomenclature JAE-HoNG PAKi and SHoicHi KAwANo2 iDepartment of Botany, Faculty of Science, Kyoto University, Kyoto 606-Ol, Japan 2Department of Botany, Faculty of Science, Kyoto University, Kyoto 606-Ol, and Institute of Genetic Ecology, Tohoku University, Sendai 980, Japan (Received December 25, 1992) Abstraet A taxonomic revision was carried out based on the new data obtained in a series of the present studies conceming chromosome morphology, fruit wall anatomy, and external morphology. Synonyms of all the taxa, keys to the sections and species of Ixeris, Ixeridium, and Crepidiastrum are provided. The present new taxonomic treatments include 25 new combinations. Ixeris was divided into 5 sections: sect. Ixeris (monotypic with only L polycephala), sect. Chinenses (including L chinensis, L graminifolia, L riparia, L strigosa, and L tamagawaensis), sect. Chorisis (monotypic with only L repens), sect. Pseudo-chorisis (incl. I. debilis and L stoloniifera), and sect. Sobolixeris (monotypic with only L longirostrata). Ixeridium comprises 12 species (L alpicola, L dentatum, L gracile, L laevigatum, L makinoanum, I. parvum, L pusillum, L pygmaeum, L siamense, L sagittarioides, L subacaule, L transnokoense, and L ]akuinsulare). Crepidiastrum was also divided into 3 sections: sect. Crepidiastrum (including C. keiskeanum, C. Ianceolatum, and C. taiwanianum), sect. Monostemma (incl. C. ameristophyllum, C. grandicollum, C. Iinguaefolium, and C platyphyllum), and sect. Paraixeris (incl. C. chelidoniifolium, C. denticulatum, C. koidzumianum, C. saxatilis, C sonchifolium, and C. yoshinoi). INTRODUCTION In connection with new evidence from critical studies on the fruit wall anatomy, external morphology aRd karyology (basic chromosorne numbers, chromosorne size, types of resting nuclei and karyotypes) of Ixeris (sensu Stebbins, l937; Kitamura, 1956), Crepidiastrum and Paraixeris (Pak and Kawano, 2990a, 1990b, l990c), it has become Recessary to redefine the limits of the above genera referred to Compositae-Lactuceae. This paper proposes Rew taxonomic accounts and nomenclatural transfers. iPresent address: Department of Biology, College of Natural Science, Kyung-Pook National University, Taegu 702-701, Korea *Contribution from Section of Systematic Botany, Department of Botany, Faculty of Science, Kyoto Universjty. 30 JAE-KoNG PAK and SHoicHi KAwANo Taxonomic Treatments Key to the genera la. Pappus persistent; achenes long-beaked. 2a. Pappus color snow-white as a whole; number of ligules per head l5-41; achenes winged with 10 costae possessing libriform fiber and sclereid-fiber cells; basic chromosome numer x=8. ••••••••••••••••••+•-•••••••••••---•t••••••••••••••••••••+•••••••••••••••••••••••••i•••••••••••••••••••+• Ixeris 2b. Puppus color yellow or dirty-white; number of ligules per head 5-12; achenes ribbed, 'with costae possessing only libriform fiber cells; basic chromosorrie number x=:7. •••••+ Jxeridium lb.Pappus deciduous; achenes short- or non-beaked; basic chromosome number x=5. ••••+•+••••••••••+••••••••••••••••••••••••••t•••••••••••••••••••••••••-•+•••••••••••••+•••••• Crepidiastrum Ixeris Cass., Dict. Sci. Nat. 24:49 (1822); Kitarn., Mem. Coll. Sci., Kyoto Imp. Univ., Ser. B, Biol. 23: 105 (1956), p.p. Syn. Chorisis DC., Prodr. 7: 177 (l838); Tzvel., Fl. URSS 29: 393 (1964). Lactuca sect. Chorisma Benth. in BeRth. et Hook., Gen. Pl. 2: 526 (1873). Ixeridium sect. Chinensia Tzvel., Fl. URSS 29: 389 (1964). Lactuca sect. Jxeris Benth., in Bentk. et Hook., Gen. Pl. 2: 526 (l873) p.p. Type: Ixeris polycephala Cass. Annual or rarely biennial, aRd perennial herbs; roots stoloniferous or tap-rooted; leaves mainly radical, but with a few cauline leaves. Infiorescence terminal, corymbose; heads few to many with relatively many fiorets (15-41). Involucres cylindrical, narrow; bracts 2-seriate, glabrous, herbaceous with scarious margins; inner bracts ovate or linear, equal, 8-10 in number, much larger and loRger than the outer bracts; outer bracts short, imbricate; receptacles fiat, naked; fiowers bisexual, ligulate, 5-toothed, yellow, white or white-purplish. Achenes fusiform, somewhat fiattened, equally acute, 10-winged; costae composed of libriform fiber cells and sclereid-fiber cells; pappus bristles many, slender, scaberulous, persistent, white. Basic chromosome number: x :8 (see Pak and Kawano, l990b). Key to the sections la. Stolons elongate; outer involucral bracts prominent, ovate. 2a. Stems leafy; heads many.••••+•+•••••••••••••••t•+••-•••+•••••••••i•-•+•••••••••i•i••••••••••• sect. Sobolixeris 2b. Stems scapose; heads few. 3a. Leaves palmately 3- to 5-cleft; intercostae of achenes 5-7 cell layers. ••••-••-•-••••• sect. Chorisis 3a. Leaves spathulate, entire or shallowly toothed; intercostae of achenes 1-3 cell layers. ...........................••.....•••••+..•••••••••••t••••••••+••+•••••••••••••••t•••-•-••••• sect. Pseudo--chorisis lb. Stolons absent; outer involucral bracts short, lanceolate. 4a. Annual, heads nodding at maturity, in false umbels; cauline leaves sagittate; achenes deeply sulcate. •••••••••••••••••••••••--••••••••••••••••••+••••••••••+-••••••••••••••••••••••••+••••••••••••+•• sect. Ixeris 4b. Perennial, heads erect at maturity, in loose corymbose; cauline leaves auriculate; achenes shallowly grooved, obtusely winged. ••••••••••-•••••••••••-•••••••••••••••••••+•••••••• sect. Chinenses Sect. Ixeris. Syn. Ixeris sect. Indo-ixeris Kitam., Bot. Mag. (Tokyo) 49: 289 (1935). Biosystematic studies on the genus Ixeris aBd its Rllied genera 31 Type: Ixeris polycephala Cass. Annual; plants glaucous; cauline leaves few, sessile, sagittate; infiorescences umbelliform; heads nodding at maturity; achenes deeply sulcate. 1. Ixeris polycephala Cass., Dict. Sci. Nat. 24: 50 (1822). Syn. Lactuca polycephala (Cass.) Benth., in Benth. et Hook., Gen. Pl. 2: 526 (1873). Lactuca matsumurae Makino, Bot. Mag. (Tokyo) 6: 56 (1892), nom. nud; Bot. Mag. (Tokyo) 12: 45 (1898). Lactuca biauriculata Vaniot et H. Lev., Bull. Acad. Geogr. Bot. 20: 143 (1909). Lactuca matsumurae var. dissecta Makino, Bot. Mag. (Tokyo) 24: 252 (1910). Ixeris matsumurae (MakiRo) Nakai, Bot. Mag. (Tokyo) 34: 153 (l920). Ixerispolycephala var. dissecta (Makino) Nakai, Bot. Mag. (Tokyo) 34: 265 (1920). Crepis bonii Gagnep., Bull. Soc. Bot. France 68: 47 (1921). Ixeris polycephala f. dissecta (Makino) Ohwi, Fl. Jap. 1246 (l953); Bull. Nat. Sci. Mus. 33:90 (1953). Distribution: Afghanistan, Assam, Bengal, Sikkirn, Nepal, Burma, Cambosia, Laos, Thailand, Vietnam, China, Japan, Korea, Nepal, Caucasia (Kitamura, 1956). Chromosome number: 2R= l6 (Ishikawa, 1921; Babcock et al., 1937; Pak and Kawano, 199e). Selected speeimens examiped. NEPAL. Kathumandu, (Hotel Royal), 12 Apr. 1963, M. Numata I (KYO); Central Nepal: Kapure, 18 Jun. 1963, M. Numata 1648 (KYO); Sindu Palchok Dist., Lamusangu, 84e m in alt., 25 May 1978, H. Tabata et al. 9892-B (KYO). CHINA. Guangdong, Guangzhou, 6 Apr. 1981, H. G. Yip 155 (KYO). Hupeb: Wuhan City, Wuchang, 40 m in alt., 7 Apr. I980, Y. Z. Long 26 (KYO); Wuhan City, 400 m in alt., 9 May 198e, Y. Z. Long 69 (KYO); Sha Tau Kok, N. T., 25 Apr. 1970, Y. H. Shin 10008 (KYO). JAPAN. Yamagata: Nishiokitama-gun, Oguni- machi, near Bentozawa-tunnel, 30e rn in alt., 3 3un.1986, S. Tsugaru & T. Takahashi 6547 (KYO). Kanagawa: Kawasaki City, Noborito, 6 May 1961, M. Mizushima, I6417 (KYO). Osaka: south of Sakai, Takaishi, Tonogi, 20 May 1953, K. Seto 3735 (KYO); Hirakata City, Kuzuha, 5 m in alt., 1 May 1981, K. Tsuchiya 150S (KYO). Okayama: Akaiwa-gun, Seto-cho, Shiono, 17 Apr. 1983, L Okubo s.n. (KYO). Ehime: Matsuyama City, 10 Apr. 1955, S. Yamamoto, 27155 (KYO). Fukuoka: Hakozaki, l1 Apr. 1932, S. Hatushima, s.n. (KYO). Kagoshima: Ohsumi, TokaraIsls., TokaraIsl., 8-1l May 1963, S. Sako 4458 (KYO); Ohshima-gun, along Kokachi-gawa, Uken-mura, Isl. Amami- Ohshima, leO m in ait., 14 Mar. 1986, G. Murata 56316 (KYO). Notes: This species is variable in leaf shape. Plants with pectiRate-pinnatifid leaves are often found aRd classified as f. dissecta (or var. dissecta). Sect. Chinenses (Tzvel.) Pak et Kawano, comb. et stat. nov. Syn. Ixeris Cass. sect. Ixeridium A. Gray, Mem. Amer. Acad. Arts 6: 397 (1859) p. p. ; Kitam., Bot. Mag. (Tokyo) 49: 281 (l935), p. p. ixeridium (A. Gray) Tzvel. sect. Chinensia Tzvel., Fl. URSS 29: 388 (l964). Type: Ixeris chinensis (Thunb.) Kitagawa Perrenial herbs; stems erect 20-40 cm in height; naked or single-leaved; heads with l6- 32 3AE-HoNG PAK and SxxoicHI KAwANo 41 ligules; achenes fusiform, IO-alata; its beaks nearly as long as the achene body. Notes: The species referred to this section no doubt belong to the genus Ixeris (sensu Pak and Kawane) rather thaR to Ixeridium. They are characterized by having slightly wiRged achenes with white pappus, and numerous ligules per head, rangiRg from 16-41. Costae of achenes possess 1-2 fiber-sclereid cell layers. The basic chromosome number of this group is x = 8 of small relative