Euonymus pseudovagans Pitard (1912: 871)

Du, Cheng, Zuo, Yunjuan & Ma, Jinshuang, 2013, Revision of three species of Euonymus (Celastraceae) from China, Phytotaxa 109 (1), pp. 45-53 : 46-50

Euonymus pseudovagans Pitard (1912: 871) . Fig. 1 : G–H & 3.

Type:— VIETNAM. Ninh-Binh, Tonkin méridional, Vô Xâ, in montibus Thung Gang , 21 October 1886, H. F . Bon 3235 (lectotype P 00276213 !, designated here, isolectotypes P 00276214 !, P 00276215 !) .

Lianas, evergreen, climbing in trees. Stems dense, with adventitious roots, to 10 m. Branches brown; twigs yellowish green, usually quadrangular. Leaves petiolate; petiole 5–8 mm long; blade thickly coriaceous, elliptic or ovate-elliptic, 7–15 × 2.5–6 cm, base cuneate, margin crenulate, slightly revolute, apex acute; lateral veins 5–7 pairs, reticulate before reaching margin, inconspicuous. Flowering when reaching canopy of trees. Inflorescences axillary, paired dichasia, peduncle 2–3 cm long, secondary peduncles 8–10 mm long; branches 2 or 4, dichotomous;. Pedicels 3–4 mm long, flowers 10–20 per inflorescence, 4-merous, 10–12 mm in diam.; sepals yellowish green, ovate-deltoid; petals yellowish green, round, margin entire; disk 4.5–5 mm in diam., 4-lobed; stamens 4, filament 1.5–2.5 mm long, anthers versatile, oblong; ovary superior, stigma rounded, locules 4, placentation axial, ovules 2 per cell. Capsules brown or yellowish brown, with dense bright white spots on sides of angles, to 1 cm in diam. Seeds with red aril.

Phenology:—Flowering April to May; fruiting September to October.

Specimens examined: — CHINA. Yunnan: Funing, Ligong, 1410 m, 15 October 1965 (fr.), 65 Wenshan Group 185 ( KUN) ; Malipo, Xiajinchang, Daxichang, 1450 m, 17 April 2012 (fl.), C . Du DC00093 ( CSH), 13 September 2012 (fr.), C . Du DC00201 ( CSH) ; Xichou, Xiaoqiaogou, 1622 m, 16 April 2012 (fl.), C . Du DC000086 ( CSH); without locality (possible in southeastern Yunnan , China), no date (fr.), Y . Tsiang 12414 ( IBSC, KUN, WUK) .

Discussion:—Based on Y. Tsiang 12414 and 65 Wenshan Group 185 from Yunnan, Euonymus pseudovagans was recorded in China by Ma (2001: 120) and in Flora of China by Ma & Funston (2008: 453). At that time, only specimens with fruits were available, but the flowers were unknown. In the present study, we observed E. pseudovagans in Malipo and Xichou counties, Yunnan, and were able to supplement the morphological details of both flowering and fruiting stages. Previous studies indicated that E. pseudovagans also occurs in Guangxi and Guizhou ( Cheng et al. 1999, Ma 2001, 2006, Ma & Funston 2008), but we were unable to confirm its occurrence in these two provinces. Based on our field surveys, the specimens from those provinces are not E. pseudovagans . In China, E. pseudovagans may be only restricted to southeastern Yunnan. Euonymus pseudovagans is similar to E. bockii Loesener (1902: 439) , but the leaves are thickly coriaceous and obviously petiolate, the margins are revolute, the dichasia have 2 or 4 dichotomous branches and the capsules have dense bright white spots on the four angles.

Typification:— The original protologue of Euonymus pseudovagans does not mention collector number, only the collection site as "Tonkin: environs de Ninh-binh (Bon)". However, the specimens at the Herbier National de Paris ( P), show the notation " Euonymus pseudovagans Pitard , sp. nov. " with the author's handwriting only on the sheets of Bon 3235 (see Fig. 3 ) from Tonkin méridional, Vô Xâ , in montibus Thung Gang , ( Ninh-Binh Province ), Vietnam. The first sheet ( P 00276213 ) is clearly annotated by Pitard and is here selected as the lectotype, the two other sheets ( P 00276214 & P 00276215 ) are therefore isolectotypes .

Euonymus mengtzeanus (Loes.) Sprague (1908: 35) (as mengtseanus).— Euonymus theifolius Wall. ex Lawson (1875: 612) var. mengtzeanus Loesener (1902: 455) Fig. 2 : A–D. Type:— CHINA. Yunnan: Mengtze [Mengzi], 1670 m, A. Henry 10684 (lectotype K 000669104!, designated here;

isolectotypes A 00049772!, E 00275644!, IBSC 0269494!, K 000669103!, MO 2196885!, NY 00337356!, US

00096047!). Fig. 4

Shrubs, to ca. 3 m tall. Branches quadrangular, twigs with obvious wings. Leaves petiolate; petiole 5.5–10 mm long; blade thinly coriaceous, elliptic or elliptic-oblong, 6–10 x 2.5–4 cm (to 15 cm long in wet places), base rounded or subtruncate, slightly oblique, margin crenulate, sometimes with black glands, apex acuminate, 7–10 mm long; lateral veins 4 or 5 pairs, reticulate before reaching margin, impressed on upper surface and prominent on lower surface. Inflorescences paired axillary dichasia, peduncle 0.8–2.5 cm long; branches 1 or 2.. Pedicels 5–12 mm long, flowers 3–5 per branch, 5-merous, 9–12 mm in diam.; sepals margins membranous, short ciliate; petals purple or sometimes light purplish red, nearly round, 4–5 mm long, margin with indistinct notch; disk 3.5–4 mm in diam., 5-lobed, lobes obtuse; stamens 5; ovary superior, stigma rounded, placentation axial, ovules 2 per cell, anatropous. Capsule obovoid, base attenuate, with 5 angles and grooves, 7–8 mm long, c. 10 mm in diam., opening by 5 lobes at maturity. Seeds ovoid, dark brown, 5–6 mm long, c. 3 mm in diam., covered by orange aril.

Phenology:—Flowering March to April; fruiting May to September.

Specimens examined:— CHINA. Yunnan: Hekou, Si Qu, Shidongjiao, 1900 m, 17 August 1953 (fl.), W . X. Li 663 ( KUN) ; Funing, Lida Qu, Ligong Gongshe, 1280 m, 10 October 1964 (fr.), Q . A . Wu 9566 ( KUN) ; Malipo, Babu, Dongzu, 1620 m, 14 May 1964 (fl.), S . Z . Wang 304 ( KUN, LBG); Laojun Shan, Houshan Forest Farm, 1700 m, 9 May 1962 (fl.), K . M . Feng 22643 ( IBSC, KUN), 26 May 1962 (fr.), K . M . Feng 22854 ( IBSC, KUN); Guan-gaw , 1200 m, 15 February 1940 (sterile), C . W . Wang 86891 ( IBK, KUN, WUK) ; Xichou, Fadou, Caoguo Shan, 1700 m, 3 May 1964 (fl.), S . Z . Wang 024 ( KUN), 1750 m, 4 April 1959 (fl.), Q . A . Wu 7252 ( KUN); Fadou, Xiaoqiaogou , 1622 m, 16 April 2012 (fl.), C . Du DC00084 ( CSH), 29 September 2012 (fr.), C . Du DC00244 ( CSH) ; Pingbian, Yiqu Mawei, Huo Shan, 1600 m, 19 October 1954 (fr.), K . M . Feng 5089 ( KUN); Xinxian, Shitouzhai, Daqing , 1600 m, 16 July 1953 (fr.), P . Y . Mao 2538 ( KUN); Yuping, Dawei Shan , 1719 m, 13 April 2012 (fl.), C . Du DC00071 ( CSH), 1471 m, 13 April 2012 (fl.), C . Du DC00074 ( CSH), 1700 m, 8 October 2012 (fr.), C . Du DC00248 ( CSH), 2000 m, 8 October 2012 (sterile), C . Du DC00253 ( CSH) ; Wenshan, Laojun Shan, 1900 m, 24 April 1962 (fl.), K . M . Feng 22234 ( IBSC, KUN); without location, 1800 m, 11 February 1933 (sterile), H . T . Tsai 51750 ( KUN) ; Guangnan, Hua-guoo-da-ching, 1550 m, no date (fl.), C . W . Wang 87706 ( IBK, IBSC, KUN, WUK) .

Discussion: — Euonymus mengtzeanus was initially affiliated with section Illicifolia Nakai (1941: 619) due to similarities in habit to E. vagans Wallich (in Roxburgh 1824: 412). Since the type specimen lacks fruit, its systematic position remains controversial. Blakelock (1951: 256), in dividing Euonymus into sections and series, treated E. mengtzeanus as a species of sect. Biloculares Rouy (1897: 158, i.e. sect. Euonymus ) ser. Myrianthi Blakelock (1951: 233) . In Flora Reipublicae Popularis Sinicae ( Cheng et al. 1999: 25), E. balansae Sprague (1941: 615) , from Pingbian County, south of Mengzi, was misidentified as E. mengtzeanus because of similarities in leaf shape. Euonymus mengtzeanus was treated as a synonym of E. balansae , a species in sect. Echinococcus Nakai (1941: 617), in the revision of Euonymus by Ma (2001: 56) and in the Flora of China by Ma & Funston (2008: 446). In a numerical taxonomic analysis, especially based on leaf epidermal characteristics, E. mengtzeanus was shown to be not closely related to E. balansae , and it should not be affiliated with sect. Echinococcus (Zheng et al. 2012).

We made extensive observations of E. mengtzeanus in areas around Malipo and Pingbian counties in the southeast Yunnan. We re-collected E. mengtzeanus from a population in Xiaoqiaogou Nature Reserve, Xichou County, and made several collections of E. mengtzeanus with flowers and fruits from the same plants in those locations. We also examined four specimens with fruit and eight with flowers in the herbarium of the Kunming Institute of Botany, Chinese Academy of Sciences. In combination with details of the type specimens and information from the original description, we determined that E. mengtzeanus should be placed in sect. Euonymus subsect. Euonymus ser. Pseudovyenomi ( Nakai 1941: 615) Blakelock (1951: 234) .

Euonymus mengtzeanus is similar to E. laxiflorus Champ. ex Bentham (1851: 333) and E. prismatomeridoides C. Y. Wu ex Ma (2001: 230) , especially in features of flowers and fruits. However, E. laxiflorus has leaves without impressed lateral vein and it has loose inflorescence branches with 5–9 flowers, while E. prismatomeridoides has long, subulate or broadly linear leaves.

Figures

FIGURE 1: Euonymus wui (A–F) and Euonymus pseudovagans (G–H). A, Branch with leaves and inflorescences; B, Flowers (front view); C, Ovary (longitudinal section); D, Ovary (cross section); E, Capsule; F, Portion of open capsules with red arillate seeds; G, Branch with leaves and inflorescences; H, Capsules. A–D from C. Du DC00017, E–F from C. Du DC00203, G from C. Du DC00093, H from C. Du DC00201.Photos by C. Du.

FIGURE 2: Euonymus mengtzeanus (A–D). A, Branch with leaves and inflorescences; B, Flower (front view); C, Capsule (lateral view); D, Capsule (front view); E, A distribution map of the three Euonymus species (● E. wui, ̝ E. pseudovagans ․ E. mengtzeanus). A–B from C. Du DC00074, C–D from C. Du DC00248. Photos by C. Du.

FIGURE 3: Lectotype of Euonymus pseudovagans, H. F. Bon 3235 (P00276213) (http://coldb.mnhn.fr/CatalogNumber/MNHN/P/ P00276213).

FIGURE 4: Lectotype of Euonymus mengtzeanus, A. Henry 10684 (K000669104) (http://apps.kew.org/herbcat/ getImage.do?imageBarcode=K000669104).