ISSN 1346-7565 Acta Phytotax. Geobot. 72 (2): 145–151 (2021) doi: 10.18942/apg.202011
Flora of Bokor National Park VIII : A New Species of Cleyera (Pentaphylacaceae), C. bokorensis
1,* 2 3 Shuichiro Tagane , Hidetoshi Nagamasu , Phourin Chhang , 4 5 6 Hoang Thanh Son , Hironori Toyama and Tetsukazu Yahara
1The Kagoshima University Museum, 1-21-30, Korimoto, Kagoshima 890-0065, Japan. *[email protected] (author for correspondence); 2The Kyoto University Museum, Kyoto University, Yoshida Honmachi, Sakyo-ku, Kyoto 606-8501, Japan; 3Institute of Forest and Wildlife Research and Development, Forestry Administration, 40 Preah Norodom Blvd, Phnom Penh, Cambodia; 4Department of Forest Plant Resource, Silviculture Research Institute (SRI), Vietnamese Academy of Forest Sciences (VAFS), 46 Duc Thang, Bac Tu Liem, Ha Noi, Vietnam; 5Biodiversity Division, National Institute for Environmental Studies, Tsukuba, Ibaraki 305-8506, Japan; 6Kyushu Open University, 744 Motooka, Fukuoka 819-0395, Japan
Cleyera bokorensis Nagam. & Tagane (Pentaphylacaceae), from Bokor National Park in southern Cam- bodia and Binh Dinh Province, central Vietnam, is illustrated and described as new. Cleyera bokorensis is a rheophytic shrub characterized by oblong-elliptic leaves with sparsely and obtusely serrate to ser- rulate margin, 7–10 pairs of secondary veins, solitary flowers, a 1.6–2.7 cm long pedicel and 6.5–10.5 mm long petals. The combination of features clearly distinguish it from C. japonica and other species of Cleyera in Indochina and surrounding countries.
Keywords: Cambodia, flora, Indochina, taxonomy, Ericales
Bokor National Park in Kampot Province, ovules in Cleyera vs. 20–100 ovules in Adinan- southern Cambodia, is known as one of the dra) and seeds 1–2 mm long, on a central axis (vs. hotspots of plant diversity in Southeast Asia less than 1 mm long on extended, forked placen- (Rundel 1999, Zhang et al. 2016). Indeed, our tas) (Keng 1972, Ming & Bartholomew 2007, botanical inventories carried out from 2011 to Nguyen 2017). 2013 resulted in the discovery of 24 new species In Cambodia, Cleyera bokorensis was first and more than 100 species recorded for the first collected on Mt. Bokor in 1933 (E. Poilane 23148 time in the country (Naiki et al. 2015, 2017, (P; barcode P04614340 — annotated as Tristyli- Tagane et al. 2015a, 2015b, 2015c 2016, 2017, um ochnaceum Merrill, and Cleyera ochnacea Tanaka et al. 2015, Toyama et al. 2016a, 2016b, DC. and P04614341 — annotated as Tristylium Yahara et al. 2016, Oguri et al. 2017, Suetsugu ochnaceum Merrill). In Flore Générale de l'Indo- et al. 2018). We here report another undescribed Chine, Gagnepain (1943) treated them as Tristyli- species, and the first report of Cleyera Thunb. um ochnaceum Merr. with Cleyera ochnacea (Pentaphylacaceae), in Bokor National Park. DC. in synonymy and Cleyera japonica Matsum. Cleyera is composed of about 24 species “var.” and Eurya ochnacea Szysz. Gagnepain distributed in Cambodia, China, India, Japan, (1943) regarded Tristylium ochnaceum (= C. och- Korea, Laos, Myanmar, Nepal, Vietnam and nacea) s.lat. as a species widely distributed from tropical America (Ming & Bartholomew 2007, Cambodia and Vietnam to mainland China, Newman et al. 2007). Cleyera is sister to Adinan- Hainan, Taiwan and Japan. dra Jack (Tsou et al. 2016), but distinguished in In recent taxonomic treatments, Cleyera och- having fewer ovules per locule (less than 20 nacea DC. and Tristylium ochnaceum (DC.) 146 Acta Phytotax. Geobot. Vol. 72
Merr. were considered to be synonyms of –)1.2–2.9 cm, leathery, adaxially pale green or Cleyera japonica var. japonica s.str. of Japan, pale brown, shiny, abaxially pale green, glabrous, Korea, China and Vietnam (Nagamasu 2006, abundantly glandular punctate on both surfaces Ming & Bartholomew 2007, Nguyen et al. 2017). when dry (Cambodian plants) or abaxially only Another variety, C. japonica var. wallichiana (Vietnamese plants), base cuneate, margin (DC.) Sealy, is in China, India, Myanmar and Ne- sparsely and obtusely serrate to serrulate, apex pal (Ming & Bartholomew 2007). It was uncer- acute to obtuse, midrib prominent on both sur- tain whether our Cleyera from Cambodia was the faces, secondary veins 7–10 pairs, slightly promi- same as either variety of C. japonica, so we com- nent to obscure on both surfaces when dry. Flow- pared it with the two varieties of C. japonica and ers axillary, solitary, nodding. Pedicels 1.6–2.7 other species of Cleyera and with related genera cm long, glabrous. Sepals 5, suborbicular, ca. 3.5 based on treatments in the literature (e.g. Gagne- mm long, glabrous, margin ciliolate. Petals 5, ob- pain 1943, Keng 1972, Li 1976, Nagamasu 2006, long-obovate to suborbicular, 6.5–10.5 × 5–6 Ming & Bartholomew 2007, Nguyen et al. 2017), mm, white, glabrous. Stamens 30–36, 4–9 mm specimens at BKF, BM, BO, FOF, HN, K, KAG, long, anthers 1.3 mm long, orange, hispid, fila- KEP, KYO, L, P, RUPP, SAR, TNS, VAFS and ment white, glabrous. Ovary ovoid, ca. 3.5 mm VNM and type specimen images on JSTOR long, glabrous; locules 3; ovules 17–26; style ca. 6 Global Plants (https://plants.jstor.org/). We con- mm long, 3-lobed at apex. Fruits ovoid-ellipsoid, cluded that the population of Cleyera in Bokor ca. 10 × 5 mm, glabrous, black when mature. National Park was distinct from C. japonica and Seeds dark reddish brown, compressed globose, from other species of Cleyera. We here describe shiny, ca. 3 mm long, 2.2 mm wide, 1.1 mm thick. and illustrate it as a new species. Etymology. The epithet bokorensis is from the name of the type locality, Bokor National Park, Taxonomic treatment Cambodia.
Cleyera bokorensis Nagam. & Tagane, sp. nov. Distribution. Cambodia (Kampot: Mt. Bo- — Figs. 1 & 2. kor), Vietnam (Binh Dinh) (Fig. 3). Most similar to Cleyera obscurinervia (Merr. & Chun) Hung T. Chang from China (Hainan and southern Habitat and Ecology. Cleyera bokorensis is a Guangxi) in having glabrous twigs and leathery oblong- rheophytic shrub. A large population was along a elliptic leaves with sparsely and obtusely serrate to ser- stream below Popokvil Waterfall in Bokor Na- rulate margin, but differing in having fewer secondary veins (7–10 pairs vs. 12–15 pairs) and longer pedicels tional Park (Fig. 1a) between 800 and 1,066 m. (1.6–2.7 cm vs. 1–1.5 cm) and longer petals (6.5–10.5 mm The riparian forest is dominated by Macaranga vs. ca. 6 mm) (Table 1). andamanica Kurz (Euphorbiaceae), Beilschmie- Typus. Cambodia. Kampot Province: Bokor National dia penangiana Gamble (Lauraceae), Syzygium Park, at edge of evergreen forest along a stream, alt. 917 formosum (Wall.) Masam. (Myrtaceae), Ficus m, 10°39′30.82″N, 104°03′05.14″E, 8 Dec. 2011, Toyama H., Tagane S., Ide T., Chhang P., Nagamasu H., Yahara T. cambodica Gagnep. (Moraceae) and Phyllanthus 1764 [fl.] (holo- KYO!; iso- Cam*, K). * ‘Cam’ indicates bokorensis Tagane (Phyllanthaceae). In Vietnam, the herbarium of the Forest Administration of Cambodia. it is commonly found along streams between 262 Shrubs, rheophytic, 2–7 m tall, evergreen. Young and 310 m where it grows with Goniothalamus twigs green, soon turning reddish brown, gla- tamirensis Pierre ex Finet & Gagnep., Polyalthia brous, old twigs grayish brown. Terminal bud sp. (Annonaceae), Areca triandra Roxb. ex elongate, conic, 0.7–1.4 cm long, glabrous. Leaves Buch.-Ham. (Arecaceae), Cleistanthus hirsutulus alternate; petiole 0.5–1.1 cm long, reddish brown Hook. f. (Phyllanthaceae) and Ardisia sp. (Primu- or light yellowish brown, glabrous; blade oblong- laceae). elliptic to narrowly elliptic, (2.5–)3.5–10.3 × (1.0
June 2021 Tagane & al. — A New Species, Cleyera bokorensis 147
Table 1. Morphological comparison between Cleyera bokorensis and C. obscurinervia. The measurements of C. obscuri- nervia is from Ming & Bartholomew (2007). Characters Cleyera bokorensis Cleyera obscurinervia Habit rheophytic shrub, 2–7 m tall tree, 6–15 m tall Leaf shape oblong-elliptic to narrowly elliptic oblong-elliptic Leaf size (2.5–)3.5–10.3 × (1.0–)1.2–2.9 cm 7–9 × 2–3.5 cm Number of secondary veins 7–10 pairs 12–15 pairs Petiole length 0.5–1.1 cm 1–1.5 cm Pedicel length 1.6–2.7 cm 1–1.5 cm Sepal length ca. 3.5 mm ca. 4 mm Petal length 6.5–10.5 mm ca. 6 mm Style length ca. 6 mm ca. 4 mm Fruit size ca. 10 × 5 mm 10–12 × ca. 7 mm
Phenology. Flowering December to March in Note 1. Two species of Cleyera, C. obovata Cambodia and December to May in Vietnam. Hung T. Chang and C. japonica have been report- Fruiting August to December in both countries. ed to be in Vietnam according to the Flora of China (Ming & Bartholomew 2007) and the Flo- Preliminary conservation assessment. Cle- ra of Vietnam (Nguyen 2017). Cleyera bokoren- yera bokorensis is known only from the two iso- sis differs from C. obovata in having an oblong- lated populations in Cambodia and Vietnam. In elliptic to narrowly elliptic leaf blade (vs. ovate to Cambodia, all populations occur within Bokor obovate-oblong in C. obovata), margin sparsely National Park, which attracts significant numbers and obtusely serrate to serrulate (vs. entire), pet- of tourists, especially at Popokvil Waterfall and als 6.5–10.5 × 5–6 mm (vs. 5–6 × ca. 5 mm) and surrounding areas on the plateau. However, the stamens 30–36 (vs. 25). From C. japonica var. area close to the habitat of C. bokorensis is cur- japonica s.str., C. bokorensis clearly differs in its rently under development for a casino, dams and sparsely and obtusely serrate to serrulate leaf residential homes. An increasing number of visi- margin (vs. entire), longer peduncle 1.6–2.7 cm tors and these developments may accelerate dis- long (vs. 0.5–1.5 cm long) and ovoid-ellipsoid turbance and are likely to negatively affect the fruits (vs. globose or ovoid). According to the key survival of Cleyera bokorensis. In Vietnam, C. of Cleyera in the Flora of China (Ming & bokorensis grows along streams in Long My Pro- Bartholomew 2007), C. bokorensis keys out to tection Forest, Phuoc My commune, Quy Nhon C. obscurinervia because of its glandular punc- city. There is a continuing decline in the quality tate leaf blade, sparsely and obtusely serrate to of the habitat as local people often build camps serrulate leaf margin, suborbicular sepals, and near the streams and clear forests to obtain fire- ovoid-ellipsoid fruits, but easily distinct accord- wood, timber and non-timber forest products. ing to the diagnosis above and other characteris- The extent of occurrence (EOO) is 1,610 km² and tics as shown in Table 1. the area of occupancy (AOO) is 24 km². We esti- mated that fewer than 2,500 mature individuals Note 2. The leaves of the Cambodian plants are in each population. Considering the habitat are densely glandular punctate on both surfaces specificity of C. bokorensis and the threats in when dry, while those of Vietnamese plants are both countries, we assess it to be Endangered densely glandular punctate only abaxially. Be- (EN) B1ab(iii) + B2ab(iii), following the IUCN cause other features, including reproductive traits criteria (2019). (e.g. flowers, number of ovules, fruit), are the 148 Acta Phytotax. Geobot. Vol. 72
Fig. 1. Cleyera bokorensis Nagam. & Tagane. a, habitat (individuals indicated by arrows). b, fruiting branch. c, flowering branch. d, terminal bud and portion of abaxial leaf surface. e, side view of a flower. f & g, top view of flowers. h, fruit. Photos: a, b, e, f & h, from Toyama 1764 (FU); c & g from Hoang Thanh Son et al. 8312 (VA FS). June 2021 Tagane & al. — A New Species, Cleyera bokorensis 149
Fig. 2. Cleyera bokorensis Nagam. & Tagane. a, fruiting branch; b, adaxial leaf surface; c, abaxial view of a leaf. d, fruit. e–f, flower. g, stamens. h, ovary and style, petals and stamens dropped. i, stamens with a petal. a–c & e–g from Toyama 1764 (FU), d from Tagane et al. 6335 (FU). 150 Acta Phytotax. Geobot. Vol. 72
and Forest Administration for permitting our fieldwork, and particularly the staff and rangers of Bokor National Park for their kind help. We are grateful to Keiko Mase who provided the drawings and the curators of the her- baria BKF, BM, BO, FOF, HN, K, KAG, KEP, KYO, L, P, RUPP, SAR, TNS, VAFS, VNM for providing us the op- portunity to examine their collections. This study was supported by the Environment Research and Technology Development Fund (S9 & 4-1601) of the Ministry of the Environment, Japan, and also by a JSPS grant from the Global Center of Excellence Program ‘Asian Conserva- tion Ecology as a basis of human-nature mutualism.’
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Received May 11, 2020; accepted August 5, 2020