Colocasia spongifolia sp. nov. (Araceae) in southern China and central Vietnam Author Matthews, Peter J. 0000-0003-2563-0976 National Museum of Ethnology, Senri Expo Park 10 - 1, Suita, Osaka 565 - 8511, Japan. & pjm @ minpaku. ac. jp; https: // orcid. org / 0000 - 0003 - 2563 - 0976 pjm@minpaku.ac.jp Author Nguyen, Van Du 0000-0003-1703-4058 Institute of Ecology and Biological Resources (IEBR) - Vietnam Academy of Science and Technology (VAST), A 11 - 18 Hoang Quoc Viet Street, Cau Giay, Hanoi, Vietnam. & Graduate University of Science and Technology - Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet Street, Cau Giay, Hanoi, Vietnam. & vandu 178 @ gmail. com; https: // orcid. org / 0000 - 0003 - 1703 - 4058 vandu178@gmail.com Author Fang, Qiong 0000-0002-0715-2184 College of Life and Environmental Sciences, Minzu University of China, 27 Zhong-guan-cun South Ave., Haidian District, Beijing 100081, China. & qiongfang 620 @ foxmail. com; https: // orcid. org / 0000 - 0002 - 0715 - 2184 qiongfang620@foxmail.com Author Long, Chun-Lin 0000-0002-6573-6049 College of Life and Environmental Sciences, Minzu University of China, 27 Zhong-guan-cun South Ave., Haidian District, Beijing 100081, China. & Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Heilongtan, Kunming, Yunnan 650204, China. & long @ mail. kib. ac. cn; https: // orcid. org / 0000 - 0002 - 6573 - 6049 long@mail.kib.ac.cn text Phytotaxa 2022 2022-03-22 541 1 1 9 http://dx.doi.org/10.11646/phytotaxa.541.1.1 journal article 20147 10.11646/phytotaxa.541.1.1 b7cc353a-a9b3-4520-8f9d-70567574e65b 1179-3163 6375098 Identification key 1. Plants with stolons; stem short to tuberous and decumbent, or rhizomatous; with multiple adaxial buds in each leaf axil; spadix with sterile appendix or not; staminodes between ovaries many to abundant ...................................................................... 2 - Plants without stolons or side-tubers; stem cylindrical, erect; a single adaxial bud in each leaf axil; spadix always with sterile appendix; staminodes between ovaries few or absent........................................................................................................................6 2. Sterile appendix long (up to ca. 10 cm ,> 2x length of male zone), thick, diam. up to 10 mm at base (wider than male zone) ......... ........................................................................................................................................................................................ C. formosana - Sterile appendix short and slender, much reduced, or completely absent ..........................................................................................3 3. Sterile appendix short (length 3.5 cm , equal to male zone), slender conical, diam. 5 mm at base (more narrow than male zone); underside of leaf blade surface pilose, main and primary lateral veins pubescent; petiole and peduncle pubescent .......................... ..................................................................................................................................................................................... C. menglaensis - Sterile appendix absent or much reduced; underside of leaf blade pubescent over whole surface, or not; petiole and peduncle not pubescent ............................................................................................................................................................................................4 4. Plant stout, petiole maximum 55 cm long; stem short (< 2 cm long, 3 cm diam.; sub-globose); inflorescence appears with leaves; peduncle little shorter than petiole .......................................................................................................................... C. gaoligongensis - Plant tall, 50–100+ cm long; stem sub-globose to elongate, decumbent, minimum 2 cm long; inflorescences appear after leaf emergence; peduncle much shorter than petiole.................................................................................................................................5 5. Blade cordate-ovate, upper surface waxy, not glossy green, often with dark purple patches; interprimary veins very prominent on underside of mature blade; sterile appendix absent (a much reduced vestige, apiculate, < 1cm ); staminodes between ovaries abundant, with flask shape and discoid apex............................................................................................................... C. yunnanensis - Blade cordate-sagittate, overall elongate-triangular with deep sinus, upper surface not waxy (wettable), glossy green, without purple patches; interprimary veins inconspicuous to slightly raised on underside of mature leaf; sterile appendix completely absent; staminodes between ovaries abundant, obovate with rounded apex ................................................................................ C. lihengiae 6. Leaf blade oblong-ovate, posterior lobes narrow and rounded; underside of blade pubescent over whole surface, including primary veins; peduncle cylindrical........................................................................................................................................... C. kachinensis - Leaf blade cordate-ovate; posterior lobes broad and rounded; no parts pubescent; peduncle three-angled ......................................7 7. Plant very large, petiole 90–140 cm ; stem erect or nearly erect, 120–135 cm long, 12–18 cm diam.; leaf blade with distinctly indented sinus, main vein and primary lateral veins purple, lamina “membranous”; peduncle green or purple; spathe ca. 33 cm long, spathe blade yellow with purple margin, almost erect or sometimes reflexing at anthesis; spadix ca. 30 cm long, little shorter than spathe ............................................................................................................................................................................. C. gongii - Moderate sized plant, petiole up to 120 cm , stem erect or decumbent with erect apex, up to 14 cm long, 5.5 cm diam.; leaf blade with shallow sinus, main vein and primary lateral veins green; lamina thick, rubbery, smooth on underside; peduncle green; spathe up to 19 cm long, spathe blade yellow without purple margin, strongly reflexed at anthesis; spadix 10–14 cm long, much shorter than spathe ..................................................................................................................................................................... C. spongifolia