Gynostemma

Huang, Xue-Yan, Nong, Dong-Xin, Huang, Bao-You, Yao, Li-Xiang, Yao, Ji-Jun, Yu, Li-Ying & Huang, Lu-Qi, 2024, Gynostemma verrucosum (Cucurbitaceae), a new species with verrucose stem from Guangxi, China, Phytotaxa 649 (3), pp. 293-300 : 298

Key to the species of Gynostemma in Guangxi ( China):

1. Berry globose, not dehiscent ..............................................................................................................................................................2 Capsule depressed-globose, naturally dehiscent when ripening ........................................................................................................4

2. Fruit stalk 7–25 mm ........................................................................................................................................................... G. longipes Fruit stalk less than 7 mm ...................................................................................................................................................................3

3. Leaves pedately 3–9-foliolate, usually 5–7-foliolate ............................................................................................... G. pentaphyllum Leaves pedately 3-foliolate................................................................................................................................................... G. laxum

4. Fruit 2-seeded, obtriangular................................................................................................................................................................5 Fruit 2–3-seeded, globose...................................................................................................................................................................6

5. Stem stout, with conspicuously verrucae .................................................................................................................... G. verrucosum Stem slender, without verrucose................................................................................................................................. G. compressum

6. Stem 3-angled, angles winged.................................................................................................................................... G. caulopterum Stem globose, striate and sulcate................................................................................................................................ G. guangxiense

The nrDNA dataset with 372 base pairs(bp) for ITS, and cpDNA dataset comprised an aligned matrix of 2791 bp with 820 bp for PsbB-PsbT, 794 bp for rpl20-rps12, 570 bp for trnH-psbA, 607 bp for trnL-trnF. The phylogenetic relationship is based on ITS sequences and chloroplast regions combined. The Bayesian inference (BI) and maximum likelihood (ML) analysis yielded phylogenetic relationships with the same topology. The phylogenetic analysis indicates that the 16 Gynostemma species are divided into three primary taxonomic clusters ( Fig. 3 ). The clade A includes G. longipes , G. pentaphyllum , G. burmanicum , G. pubescens , G. simplicifolium and G. laxum with common morphological characteristics of globose and not dehiscent berries, and G. microspermum with globose and dehiscent capsules. Clade B includes G. yixingense , G. laxiflorum and G. cardiospermum which belong to the subgenus Trirostellum with campanulate capsules, and long rostriform and persistent styles. Clade C includes five species G. pentagynum , G. guangxiense , G. compressum , G. caulopterum , and G. verrucosum , in which G. verrucosum and G. caulopterum form sister species (PP=0.84, BP=98%), sharing in compressed obtriangular and dehiscent capsules. The result is slightly different from the results of Gan’s (2023) phylogenetic analysis basing on chloroplast genomes and Zhang’s (2019) study. Since this molecular analysis based on only five DNA fragments, it is necessary to further study.

Figures

FIGURE 3. Phylogenetic relationship among Gynostemma verrucosum and representative species of Gynostemma base on combined DNA date (One nuclear and four chloroplast regions). The numbers under the nodes are maximum likelihood and Bayesian inference bootstrap percentages, respectively.