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| Persicaria rotunda (Z.Z.Zhou & Q.Y.Sun) Bo Li
in Guo, Chen, Chen & Li, 2019.
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Abstract
Persicaria jucunda (Meisn.) Migo var. rotunda (Z.Z.Zhou & Q.Y.Sun) Bo Li was originally published in the genus Polygonum L. and treated as a variety of P. rotundum Meisn. [≡Persicaria jucunda (Meisn.) Migo]. After carefully comparing the macro- and micro-morphological characteristics of the achenes, leaf epidermis and tepals and the habitat between the variety and its typical variety, we confirmed that P. jucunda var. rotunda is clearly different from P. jucunda and should not be treated as a variety, but be raised to a specific rank as P. rotunda (Z.Z.Zhou & Q.Y.Sun) Bo Li. The species is distylous and could be easily distinguished from all other Persicaria taxa by a combination of morphological characters, such as completely decumbent leafless basal branches, almost sessile leaves, linear-lanceolate with rounded leaf bases, spicate, short and dense inflorescences, slender pedicels longer than bracts and dimorphic flowers and achenes. P. rotunda is endemic to several large wetlands of eastern China and usually occurs as one of the dominant species in some plant communities.
Keywords: Distyly, micro-morphology, new combination, Polygonum, variety
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| Figure 1. Persicaria rotunda (Z.Z.Zhou & Q.Y.Sun) Bo Li A plant community with P. rotunda |
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| Figure 1. Persicaria rotunda (Z.Z.Zhou & Q.Y.Sun) Bo Li B close-up view of an individual in situ C an individual showing branches D leaves E leaf base F ocrea G inflorescences. Scale bars: 1 cm (E, F, G). |
Persicaria rotunda (Z.Z.Zhou & Q.Y.Sun) Bo Li, comb. &, stat. nov.
≡Polygonum jucundum Meisn. var. rotundum Z.Z.Zhou & Q.Y.Sun, Acta Phytotax. Sin. 45(5): 714 (713–718; figs.). 2007. Type: CHINA. Anhui Province, Dongzhi County, Shengjin Lake, on riparian plains, Alt. 6–20 m, 4 October 2006, Z.Z.Zhou 0602 (holotype: PE!, isotype: ANU).
≡Persicaria jucunda (Meisn.) Migo var. rotunda (Z.Z.Zhou & Q.Y.Sun) Bo Li, Phytotaxa. 91 (1): 24. 2013.
Diagnosis: This species is easily distinguished from other Persicaria taxa by its completely decumbent leafless basal branches, almost sessile leaves, truncate, linear-lanceolate leaf blades, spicate, short and dense inflorescences, pedicels longer than bracts and dimorphic flowers and achenes. It occurs as one of the dominant species of some lakeshore plant communities in several large wetlands of northern Jiangxi and south-western Anhui provinces, eastern China.
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| Figure 2. Line drawing of Persicaria rotunda (Z.Z.Zhou & Q.Y.Sun) Bo Li A branches and inflorescences B ocrea and leaf C inflorescence D S-morph flower and its pistil E L-morph flower and its pistil F S-morph achene G L-morph achene. |
Distribution and habitat: Persicaira rotunda is currently known only from several wetlands in north of Jiangxi Province and southwest of Anhui Province, eastern China and mainly grows in marshy and grassy areas around Daguan Lake, Lihu Lake, Longgan Lake, Poyang Lake Qingcao Lake, Shengjin Lake, Shimeng Lake and Wuchang Lake, which are several small to large lakes located near the Yangtze River. It usually occurs as one of the dominant species of some lakeshore plant communities (Fig. 1A).
Yue-Ning Guo, Shao-Feng Chen, Ming-Lin Chen and Bo Li. 2019. Persicaria jucunda var. rotunda (Polygonaceae, Persicarieae), A Distinct Distylous Taxa raised to Specific Rank. PhytoKeys. 126: 127-138. DOI: 10.3897/phytokeys.126.35442
