Gynostemma verrucosum L.Q.Huang, D.X.Nong & X.Y.Huang

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 : 295-297

Gynostemma verrucosum L.Q.Huang, D.X.Nong & X.Y.Huang , sp. nov. ( Fig. 1 )

Type:— CHINA. Guangxi Zhuang Autonomous Region, Longlin county, Deer town, Tianba village, at moist places along small stream valleys, alt. 1600–1700 m, 18 July 2022, Dong-Xin Nong et al. 451031220718027 LY (holotype GXMG, isotype GXMG).

Diagnosis:— Gynostemma verrucosum is morphologically similar to G. compressum in its obtriangular fruit, but distinguished by its larger seed with a serrate and sulcate margin, stem subhemispheric verrucose, and sparsely puberulent nodes, leaves usually 9-foliolate (vs. 7-foliolate in G. compressum ) and with larger central leaflet.

Description:— Perennial herb. Stem stout, 3–10 m high, 3–5 mm in diam., branched, sparsely puberulent at nodes, conspicuously verrucose, verrucae semicircular, 1–3 × 1–2 mm. Tendrils filiform, apex bifid. Leaves pedate, (5–)9(– 11)-foliolate; petioles 10–22 cm, glabrous, grooved; petiolule 1–5 mm, pilose, sulcate; leaflets oblong or obovateelliptic, papery, both surfaces sparsely pilose, base cuneate, margin serrate, apex acuminate, mucronate; central leaflet 7–15 × 2–4 cm; lateral veins 10–12 pairs, recessed adaxially, slightly raised abaxially; lateral leaflets smaller. Plants dioecious. Male flowers in panicles, axillary, 4–11 cm long; bracteoles linear, ca. 5–8 mm; pedicels 4–5 mm; calyx segments 5, triangular, 1–1.5 × 0.5–0.8 mm; corolla segments 5, ovate-lanceolate, 1.5–2 × 0.8–1.0 mm, both surfaces finely warty; filaments very short, connate; anthers ovoid. Female flowers in panicles, axillary, peduncles glabrous or sparsely puberulent; pedicel filiform, 1–2 cm, glabrous, bracteole 1, linear; calyx segments 5, triangular, 1–1.5 × 0.8–1.0 mm; corolla segments 5, ovate-lanceolate, 2–3 × 1–1.5 mm, apex acuminate; ovary 2-locular, each locule with 1 ovule; styles 2, free; stigmas bifid. Fruit baccate, compressed, obtriangular, 8–10 × 14–18 mm, glabrous, apex with persistent perianth and styles; fruit stalk filiform, 3–7 cm. Seeds 2, brownish, obtriangular, ca. 5–6 mm, apex ca. 6–7 mm in diam., both surfaces spiniform-tuberculate, margin serrate and sulcate, acute verrucae inside groove; umbilical contraction rounded and punctuate, slightly skew. Flowering in June–August, fruiting July–September.

Other specimens examined:— The same locality, 20June 2023, Xue-Yan Huang et al.451031bb-03-033 (paratype, GXMG!) ; the same locality, 10 April 2014, Dong-Xin Nong et al. 451031140410044 LY (paratype, GXMG!) .

Etymology:— The specific epithet of the new species is derived from the stem with v errucose structures. A Chinese name is proposed here as “ ḣẕäpfi ”, Chinese pinyin: Yóu Jīng Jiǎo Gǔ Lán.

Distribution and ecology:— Currently, Gynostemma verrucosum is only known from the type locality and one other village also in Deer town, Longlin county, northwestern Guangxi, China. It grows in broad-leaved evergreen forest in moist places along small mountain valleys at an elevation of 1600–1700 m, where it is rare. The two distribution sites have a limited number of populations, one about 50 m 2 and the other about 10 m 2, with a total population of about 100 plants. The environment in which it grows is generally affected by human activities such as cultivation, deforestation and grazing, however since its distribution site is far away from villages, it is not immediately affected by the habitat loss. Live plants collected from the type locality are currently cultivated and grow well in Guangxi Botanical Garden of Medicinal Plants (Garden number: 20220198).

Although G. verrucosum shows good growth in cultivation, it is not clear what factors affect the dynamics of natural populations. Gynostemma species are frequently used as medicinal or food plants, so its conservation and sustainable utilization deserve to be further studied.

Taxonomic relationship:— Non-spherical capsules with non-rostrate persistent styles is a rare feature in the genus Gynostemma . Up to now, three species were reported having this character ( Gan et al. 2023), named G. guangxiense X.X.Chen & D.H.Qin (1988: 495) , G. compressum X.X.Chen & D.R.Liang (1991: 13) , G. caulopterum S.Z. He (1996: 207) . Although the fruits of these three species are considered to be berries in some literature, after years of field investigation and cultivation observation, it was found that the fruits are naturally dehiscent when ripening, so should be classified as capsules ( Chen et al. 2011, Su 2020). Among them, the new species most resembles G. compressum in fruit shape, seed shape and number of seeds, but differs in its stouter stem, larger leaflets, larger fruit and the ornamentation on the seed surface. It also resembles G. caulopterum in the similar leaf shape and size while it differs in the morphology of stem. Furthermore, it resembles G. guangxiense especially the 7-foliolate type in its subcylindrical stem, but strongly differs in the fruit shape and leaf size. In conclusion, it is obviously distinguished from these three species in having verrucose stem, (5–)9(–11) leaflets, petiole length more than 10 cm, and large spiniform-tuberculate obtriangular seeds. The comparisons between G. verrucosum and these three species are provided in Table 2 and Figure 2 .

Figures

FIGURE 1. Gynostemma verrucosum: A. Habit of plant; B. Male inflorescence; C. Male flower; D. Female inflorescence and young fruits; E. Female flower; F. Fruits; G. Seeds; H. Seeds, top view with acute verrucae inside groove; I. Cross section of stem; J. Node; K. Side view of leaflet. Photos by Xue-Yan Huang and Dong-Xin Nong, plate design by Dong-Xin Nong. The photographs are from Dong- Xin Nong et al. 451031220718027LY.

FIGURE 2. Gynostemma compressum: A. Habit of flowering and fruiting plant; B. Fruits; C. Seeds; D. Cross section of stem. G. guangxiense: E. Habit of flowering and fruiting plant; F. Fruits; G. Seeds; H. Cross section of stem. G. caulopterum: I. Habit of flowering and fruiting plant; J. Branch with fruits; K. Seeds; L. Cross section of stem. Photos by Xue-Yan Huang and Dong-Xin Nong, correction and design by Dong-Xin Nong.