Four new species of Begonia (Begoniaceae) from Vietnam: B. abbreviata, B. calciphila, B. sphenantheroides and B. tamdaoensis Peng, Ching-I Yang, Hsun-An Kono, Yoshiko Jung, Ming-Jer Nguyen, Tien Hiep Phytotaxa 2015 2015-08-14 222 2 83 99 7SF2F [164,382,662,689] Magnoliopsida Begoniaceae Begonia Plantae Cucurbitales 6 89 Tracheophyta species calciphila   Type:—  VIETNAM. Ninh Binh Province, Nho Quan District, Cuc Phuong National Park, near Khu Thung Tam Park Center(previously Bong Village), 20°21’01”N, 105°35’38”E, elev. ca.   400 m.On surface of steep limestone rocky slope in broadleaf forest, semishaded, occasional. Sterile plants collected on  18 Nov 2004; type specimen (with flowers) pressed from plants cultivated in the experimental greenhouse,  16 Feb 2011. Ching-I Peng, Wai-Chao Leong, Shin-Ming Ku, Nguyen Tien Hiep& Mai Van Sinh20226( holotype: HAST 139793; isotypes: A, CAS, E, K, KEP, HN, MO, P) Îñkȁầ   Begonia semicavaIrmsch., in sched. Herbs perennial, monoecious, lithophytic. Rhizomescreeping, to 30 cmor longer, internodes 1.5–4.5 cmlong, 6–8 mmacross, reddish or whitish hirsute, hairs 3–3.5 mmlong, glabrescent. Stipulesovate, 7–12 mmlong, 4–7 mmwide, apex caudate, margin entire, abaxially hirsute, hairs 1.5–3.5 mmlong. Leavesalternate; petiole brownish, 2–7 cmlong, villous, hairs 3.5–4 mmlong, brownish or reddish; leaf blade orbicular-ovate to ovate, apex acute, base obliquely cordate, 7–10.5 cmlong, 5.5–8.5 cmwide, margin undulate, densely ciliate; primary veins 6–8, palmate, veinlets reticulate; adaxially sparsely or densely scabrous, trichomes ca. 1.5 mmlong; abaxial surface reddish-hirsute on veins, trichomes multicellular, ca. 1 mmlong. Inflorescenceaxillary, with 2–5 flowers in dichasial cymes, peduncle tinged reddish, ca. 8 cmlong, glabrous; pedicel 8–9 mmlong, glabrous. Bractsovate, margin sparingly reddish ciliate, 3.5–4 mmlong, 2.5–3 mmwide. Staminate flower: tepals 4, outer 2 orbicular-ovate to ovate, margin entire, white or tinged pinkish, 9–15 mmlong, 9–13 mmwide, abaxially sparsely reddish-hirtellous; inner 2 oblanceolate, white, 11–13 mmlong, 3.5–4 mmwide; androecium zygomorphic, stamens 20–25, yellow, filaments 0.8–1 mmlong, anthers ca. 1.5–1.7 mmlong. Carpellate flower: tepals 3, glabrous, outer 2 orbicular or suborbicular, tinged pinkish, 12–14 mmlong, 12–13 mmwide, margin entire; inner 1 oblanceolate, 8–10 mmlong, 3–5 mmwide, white; ovary trigonous-ellipsoid, pinkish, 7–8 mmlong, 4–5 mmacross, glabrous, 3-winged, abaxial wing crescent-shaped, 3–5 mmtall, lateral wings 2–3 mmtall; styles 3, ca. 4 mmlong, fused to 1/3 at base, bifurcating with yellow stigma forming a continuous Ushaped papillose band. Capsuletrigonous-ellipsoid, 7–8 mmlong, 4–5 mmacross, abaxial wing crescent-shaped to elliptic, 8–9 mmtall, lateral wings crescent shaped, 3–4 mmtall. Seedsmany, ellipsoid, truncate at both ends, brownish, 0.4–0.5 mmlong, 0.2–0.25 mmthick.   Ecology and distribution:—Endemic to limestone karst areas in Cuc Phuong National Park, Ninh Binh Province, Vietnam( Fig. 3), elev. 320– 400 m. It grows on steep rocky slope surface or rock crevices in semishaded or shady broad-leaved forest.   Etymology:—The epithet 'calciphila'refers to the new species’ definite preference to limestone substrate. Although the name ‘  Begonia semicavaIrmsch.' has appeared on some specimens in Vietnamese herbaria (CPNP, HNU) and checklists ( Frontier Vietnam1994, 2002; Ho 1991), it was based on unpublished annotations by the late Dr. Edgar Imscher. This unpublished name has been excluded from the checklist of Southeast Asian  Begonia( Hughes 2008).  Additional specimen examined:—  VIETNAM. Ninh Binh Province, Cuc Phuong National Park, collected on limestone mountain,  Oct 1964,  Ngoc Bichs. n.( HNU);  Bong, Cuc Phuong National Park.  1 December 1969,  Nguyen Huu Hien B442( CPNP);  Ninh Binh Province, Nho Quan District, Cuc Phuong National Park, CP117. Hillsouthwest of helipad, primary forest on limestone slope, growing on rock crevice under dark forest floor, common, elev.  320–405 m, 20°21'00"N, 105°36'00"E, 18 November, 1999.  D.D. Soejarto, N. T. Hiep, N. M. Cuong, N. Q. Binh, N. X. Tamand M. V. Xinh11012( CPNP);  Ninh Binh Province, Cuc Phuong National Park, CP213. Dan village, limestone mountain near ranger station, in primary forest, elev.  350 m, 20°18'97"N, 105°37'75"E,  14 August 2000,  N. M. Cuong, D. T. Kienand M. V. Sinh961( CPNP);  Ninh Binh Province, Cuc Phuong National Park, CP2000. Near Bong, crowded in the herbaceous storey under evergreen broad-leaved forest, creeping herb  20 mlong, 20°21'05"N, 105°35'83"E, 13 November, 2000,  N. T. Hiep4231( CPNP).   FIGURE 6.  Begonia calciphilaC.-I Peng. A, Habit; B, Stipule, abaxial view; B’, Stipule, adaxial view; C, Bract; D, Staminate flower; E, Carpellate flower; F, Androecium, F’, stamens; G, Style and stigma; H, Cross section of ovary; I, Fruit. All from C.-I Peng et al. 20226(HAST). Line drawing by Ming-Chao Yu.  Leaf anatomy and vestiture:—Adaxial surface with sparse glandular trichomes ( Fig. 4D); cross section ca. 220 μm thick, epidermis single-layered on both surfaces, hypodermis absent ( Fig. 4E); abaxial surface with sparse glandular trichomes and multiseriate trichomes on veins, stomata complex single, helicocytic, subsidiary cells (5–)6 ( Fig. 4F).   FIGURE 7.  Begonia calciphilaC.-I Peng. A, Habit and habitat; B, Leaf, adaxial surface; C, Cultivated plant; D, Portion of rhizome, showing indumentum, petioles and stipules; E, Bracts; F, Cross section of ovary; G, Seed SEM; H, I, Inflorescence; J, Fruit. [All from C.-I Peng et al. 20226(HAST)].  Chromosome cytology:—The Asian section  Coelocentrumconsistently shows the chromosome number of 2 n= 30 ( Peng et al.2012, 2013, 2014a), with the exception of some probable intraspecific autotriploid individuals with 2 n= 45 in  B. longgangensisC.-I Peng & Yan Liu (2013: 54–44: 2) ( Peng et al.2013). In this study, the diploid count of 2 n= 30 was documented for  Begonia calciphila( Fig. 5B). The 30 chromosomes gradually varied from ca. 1.0 to 2.0 μm long. The centromere positions of most chromosomes were uncertain. However, several chromosomes were clearly metacentric. Satellites were not observed.  Notes:—  Begonia calciphilashares the long creeping habit with  B. auritistipulaY.M. Shui & W.H. Chen (2005: 357), a calciphyte in southwestern Guangxi, China. The new species however differs from the latter in the petioles 2–10 cmlong (vs. 9–22 cm); leaves orbicular-ovate with an acuminate apex (vs. ovate with an acute apex); leaf adaxial surface scabrous (vs. rugose and setulose); stipules villous (vs. glabrous); and petioles villous (vs. retrorsely hirsute). 2004-11-18 Vietnam Nho Quan District 400 20.350279 Khu Thung Tam Park Center 21 105.593895 Cuc Phuong National Park 6 89 400 Ninh Binh 2011-02-16 A, CAS, E, K, KEP, HN, MO, P Peng & Wai-Chao Leong & Shin-Ming Ku & Nguyen Tien Hiep & Mai Van Sinh Vietnam 6 89 HAST 139793 2 holotype 1964-10 HNU Ngoc Bich Vietnam Cuc Phuong National Park 6 89 1 Ninh Binh 1969-12-01 CPNP Nguyen Huu Hien Vietnam Cuc Phuong National Park Bong 6 89 B442 1 N, T, M, Q, V, CPNP November & D. D. Soejarto & Hiep & Cuong & Binh & X. Tam & Xinh Vietnam Nho Quan District 363 7 90 20.35 Hill 21 105.6 Cuc Phuong National Park 6 89 CP117 1 Ninh Binh 2000-08-14 N, M, T, V, CPNP Cuong, D. & Kien & Sinh Vietnam 350 Dan village Cuc Phuong National Park 7 90 CP213 1 Ninh Binh N, T, CPNP November & Hiep Vietnam 20 20.351389 Near Bong Cuc Phuong National Park 7 90 CP2000 1 Ninh Binh