Ottelia fengshanensis, a new bisexual species of Ottelia (Hydrocharitaceae) from southwestern China Author Li, Zhi-Zhong Author Wu, Shuang Author Zou, Chun-Yu Author Liu, Yan Author Hu, Guang-Wan Author Lehtonen, Samuli Author Wang, Qing-Feng Author Chen, Jin-Ming text PhytoKeys 2019 135 1 10 http://dx.doi.org/10.3897/phytokeys.135.38531 journal article http://dx.doi.org/10.3897/phytokeys.135.38531 1314-2003-135-1 17B55881885655AE9977FC1859D704AF Ottelia fengshanensis Z.Z.Li, S.Wu & Q.F.Wang sp. nov. Fig. 3 Description. The new species is similar to Ottelia guanyangensis in having bisexual flowers, three stamens, but differs through having (3)-4 flowers in each spathe (vs. 2-5), white styles (vs. yellow), green leaves (vs. dark green) and by fruits which are tiny winged (vs. obviously winged). Type. CHINA. Guangxi, Hechi City, Fengshan County, elev. 507 m, 24°34'20"N , 107°10'17"E 11 September 2018, Z. Z. Li & S. Wu-Otte51 (holotype HIB-lzz51!). Annual or perennial herb. Rhizome, short. Leaves entirely submerged, dark green and opaque, linear or oblong, 30-70 x 8-14 cm, base rounded, apex acute or obtuse; longitudinal veins 9; midrib conspicuous, stretched to the apex, becoming trinerved with obvious cross-veins at a distance of 5-7 cm from the base; petiole smooth, green, 8.0-10.0 cm long, the base expanded into a sheath. Spathe oblate, ca 3. 0 x ca. 3.5 cm, warty along edges or smooth, longitudinally ribbed and winged on the lateral margins, containing 3-4 (3) flowers; flowers bisexual; sepals reddish green, 1.0-1.5 x ca. 0.5 cm, with longitudinal ribs; petals white with yellow base, obovate, ca. 2.0 x ca. 2.0-2.5 cm, with longitudinal pleats; stamens 3, opposite to sepals, anthers elliptic, connective obscure, filaments 3.0-5.0 mm long; glands 3, 0.5-1.0 x 0.5-1.5 mm, opposite to petals, pale yellow. Ovary hexagonal-cylindric to the cylinder, 5-10 cm long, with 3 carpels; styles 3, white, slender and hairy, 1.2-1.5 cm long, stigma bifid, divided to base; stigmas 6, liner and hairy, ca. 8 mm long. Fruit a hexagonal-cylindric capsule, with 6 inconspicuous wings, dark green, with persistent calyx, 4.0-9.0 cm x ca. 6.5 mm, always longer than spathe. Seeds numerous, fusiform, ca. 1.0 mm long, both ends hairy. Pollen, subglobose, ca. 40μm in diam, with spiny granules. Figure 3. Illustration of Ottelia fengshanensis Z.Z.Li, S.Wu & Q.F.Wang. Drawn by Shuai-Jie Li. Figure 4. Phylogenetic tree and PTP analysis of O. fengshanensis sp. nov. and Blyxa japonica as an outgroup. Posterior probabilities (PP> 0.70) and bootstrap values (BS> 70) based on Bayesian Inference and maximum likelihood (ML) analysis are shown above the branches. Distribution and habitat. Ottelia fengshanensis is known from a single population in Fengshan County, Guangxi Province, China. The species inhabits a karst river less than 1.5 m in depth. Due to the complex underground river system in the karst region, it is probable that the species occurs in nearby areas as well. Conservation status. Only one population of new species was found at Fengshan County, Guangxi Province, China. Although it might be distributed in adjacent karst rivers. Until now, approximately 50-100 individuals were found in a single population. However, there is not enough information on population size and dynamics. According to the IUCN Red List Categories and Criteria ( IUCN 2017 ), we suggested that the species be evaluated as Data Deficient (DD). Phenology. The new species was found in flower from April to November. Etymology. The epithet is derived from the name of Fengshan County, which is the only known locality of occurrence. Other specimens examined (paratypes). CHINA. Guangxi, Hechi City, Fengshan County, elev. 507 m, 11 September 2018, Z. Z. Li & S. Wu Otte 056 (HIB!)