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| Sagittaria siamaginashi Shiga & K. Itoh, in Shiga, Kato, Suzuki, ... et Itoh, 2022. DOI: 10.18942/apg.202022 |
Abstract
A new species of Sagittaria (Alismataceae), S. siamaginashi, characterized by a cylindrical branch with numerous tubercles in each leaf axil, is described from Thailand and Myanmar. The scapes and inflores- cences were not seen in nature, but gibberellin-treated individuals flowered under cultivation. In floral morphology, S. siamaginashi is similar to the Chinese endemic, S. lichuanensis. A phylogenetic study based on DNA sequences of the internal transcribed spacer and chloroplast rpl16 intron, psbA–trnH spacer and trnC–petN (ycf6) spacer regions showed that S. siamaginashi and S. lichuanensis were sister taxa. A key to the taxa of Sagittaria in E and SE Asia is also provided.
Keywords: psbA–trnH spacer, rpl16 intron, Sagittaria aginashi, Sagittaria lichuanensis, Sagittaria potamogetifolia, Sagittaria tengtsungensis, trnC–petN (ycf6) spacer
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| Holotype of Sagittaria siamaginashi Shiga & K. Itoh, sp. nov. (A. Tanutong 238-D) a, Magnified view of cylindrical branches (black arrows) with tubercles (white arrows) is also shown (b). |
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| Sagittaria siamaginashi Shiga & K. Itoh, sp. nov. Habit (a, Khun Wang, Mae Wang District, Chiang Mai Province, Thailand, August 12, 2004), flowering plant (b), branching inflorescence (c), staminate flower (d), pistillate flower (e), leaf (f), lateral leaf lobe apex (g), cross section of petiole in middle (h), sheath and tubercles (i), cylindrical branch with tubercles [dorsal (j) and ventral (k)], cylindrical branches with tubercles removed (l), and mature tubercles (m). Images in b–m are photographs of plants in cultivation. Inflorescences (b–e) were produced after plants were treated with gibberellin (see main text for details). |
Sagittaria siamaginashi Shiga & K. Itoh, sp. nov.
Haec species nova Sagittariae lichuanensi et S. aginashi proxime affinis est; sed ab ea axe axillari bulbifero sylindraceo et bulbillis pleiomeris (15–50) differ.
Etymology. The specific epithet is derived from the former name of Thailand, Siam and the related Sagittaria aginashi. Dr. Jiro Harada, who originally found the species in 1986 (Harada et al. 1987), referred to the species as ‘Siam aginashi (Sagittaria sp.)’ in his publications (e.g. Harada et al. 2001, 2002, Niitsu et al. 2003, 2004a, 2004b, Suzuki et al. 2005).
Etymology. The specific epithet is derived from the former name of Thailand, Siam and the related Sagittaria aginashi. Dr. Jiro Harada, who originally found the species in 1986 (Harada et al. 1987), referred to the species as ‘Siam aginashi (Sagittaria sp.)’ in his publications (e.g. Harada et al. 2001, 2002, Niitsu et al. 2003, 2004a, 2004b, Suzuki et al. 2005).
Thail name. Nor doa (Chiang Mai Province), Phak Gam (Northeast Thailand).
Distribution and habitat. Thailand and Myanmar (Fig. 1). In ponds, marshes, riversides and paddy fields.
Takashi Shiga, Syou Kato, Katsuyoshi Suzuki, Kazumasa Tsubota, Siriporn Zungsontiporn, Tanchanok Jongrukthai, Ansaya Promma, Akekarat Tanutong, Mu Mu Aung, Norio Tanaka, Qixiang Lu and Kazuyuki Itoh. 2022. Sagittaria siamaginashi (Alismataceae): A New Species from Thailand and Myanmar. Acta Phytotax. Geobot. 73(1); 35-47. DOI: 10.18942/apg.202022
