王喜龍　王程旺　李劍武

Abstract：? Medog County， Tibet， China is located at the junction of the Eastern Himalaya and IndoBurma region， one of biodiversity hotspot in Himalaya areas， which is the core area of Yarlungzangbo Grand Canyon National Nature Reserve. During our botanical survey in Medog County of Southeast Tibet. Two new records to flora of China， Ceratostylis radiata J. J. Sm. and Bulbophyllum psychoon Rchb. f. （Orchidaceae）， are described and illustrated. Ceratostylis radiata has white flower， starshaped without colored spot， with short stem 2-2.5 cm， lip 3-lobed. Bulbophyllum psychoon is similar to B. levinei， but this species can be easily identified by its petals ovate， apex obtuse. Both of the voucher specimens were deposited in Herbarium of XZ and PE. Both of orchids were original distributed in India， Myanmar and Vitenam. The discovery of the two new record species in Medog， enriches the plant species in Southeast Tibet of China， which indicates that there is a certin relationship between the flora of Medog and the original distribution areas， and also confirms that Medog is a subtropical region with the species of distribution elevation above the orginal distribution range， and delayed flowering period. Discovery of this new record orchid species further highlights the value for biodiversity conservation of Southeast Tibet， China， and calls for more comprehensive exploration on botanical survey， study， and conservation in this region.

Key words： new record， Orchidaceae， Ceratostylis radiata， Bulbophyllum psychoon， Tibet， China

摘要：? 中國(guó)西藏墨脫縣位于東喜馬拉雅和印緬交界地區(qū)，是雅魯藏布江大峽谷國(guó)家級(jí)自然保護(hù)區(qū)的核心區(qū)域，是喜馬拉雅生物多樣性熱點(diǎn)地區(qū)之一。該文通過(guò)對(duì)中國(guó)西藏墨脫的科學(xué)考察，報(bào)道了中國(guó)蘭科植物2個(gè)新記錄種，即西藏牛角蘭（Ceratostylis radiata）和格當(dāng)石豆蘭（Bulbophyllum psychoon），并提供了描述和圖片。西藏牛角蘭花為純白色，花輻射對(duì)稱(chēng)，唇瓣3裂，莖長(zhǎng)2～2.5 cm，明顯區(qū)別于該屬內(nèi)其他種。格當(dāng)石豆蘭與齒瓣石豆蘭（Bulbophyllum levinei）相似，但不同之處在于格當(dāng)石豆蘭的花瓣卵形，先端銳尖。憑證標(biāo)本分別保存于西藏自治區(qū)高原生物研究所（XZ）和中國(guó)科學(xué)院植物研究所（PE）標(biāo)本館中。2個(gè)新記錄種原分布均在印度、緬甸和越南等地區(qū)，在中國(guó)西藏的發(fā)現(xiàn)說(shuō)明了中國(guó)西藏墨脫的植物區(qū)系和原分布地有一定的關(guān)系，同時(shí)也印證了中國(guó)西藏墨脫屬于亞熱帶地區(qū)，且2個(gè)新記錄種的分布海拔超出了原分布地范圍，開(kāi)花的時(shí)間也相對(duì)推遲。此新記錄種的發(fā)現(xiàn)對(duì)摸清該區(qū)植物種類(lèi)和豐富中國(guó)西藏植物區(qū)系提供了更加詳實(shí)的資料。

關(guān)鍵詞： 新記錄， 蘭科， 西藏牛角蘭， 格當(dāng)石豆蘭， 西藏， 中國(guó)

Southeast China is a global biodiversity hotspot located at the junction of the Eastern Himalaya and IndoBurma region （Myers et al.， 2000; Mittermeier et al.， 2005）. Medog is located in the Southeast Tibet Autonomous Region， China， and at the lower branch of Yarlungzangbo River. There is a subtropical warm humid climate caused by Indian Ocean and South Asian monsoon， which brings moisture along the Yarlungzangbo River. The area consists of a diverse series of ecosystems from alluvial grasslands， subtropical broadleaved forests and rain forests to alpine meadows above the tree line at an altitudinal range of 150-6 000 m above sea level. In recent years， many new species have been discovered in Medog， e.g. for Orchidaceae （Lai & Jin， 2012; Huang et al.， 2013; Wang et al.， 2017）， which indicates that the biodiversity survey in this region have space to carry out. During our botanical survey in Medog County of Southeast Tibet Autonomous Region， China， in November 2017， two new records of orchid species in China，Ceratostylis radiata J. J. Sm. and Bulbophyllum psychoon Rchb. f.， were found and reported as below.

西藏牛角蘭（新擬）Fig. 1

Ceratostylis radiata J. J. Sm.， in Fl. Buitenz. 6： 295. Fig. 225， 1905; Schechter， Beilb. Bot. Jahrb. 104. 45（3）： 21. 1911; J.J. Sm.， Fed. Repert. 32： 213. 1933; Baker & Bakhuizen， Fl. Java 310. 1968; Seidenf.， Bot. Tidsskr. 65（1-2）： 132. 1969; Op. Bot. 89： 115. 1986; Ceratostylis linearifolia Ridl.， Fl. Malay Pen. 4： 110. 1924; Holttum， Orchids of Malaya， Fl. Malaya 495. 1957.

Ceratostylis Blume （1825） consists of 100 species distributed from tropical Asia （India， Indonesia） to New Guinea and the Pacific Islands （Pearce & Cribb， 2002）. There are four species C. hainanensis， C. himalaica， C. siamensis and C. subulata in China （Chen et al.， 2009; Li et al.， 2015）.

Epiphytic herbs. Stems short， clustered， ca. 2-2.5 cm long， 5 mm thick， covered by 2 membranous sheaths， sheath tubular， 4-5 × 1-1.5 cm， apex acuminate. roots growing from base of stem. ca. 1 mm thick， 10 cm long. Leaves linearlanceolate， elongated， 15-25 × 1.4-2.2 cm， apex acute， slightly asymmetry， midvein slightly concave above， slightly convex below， basally ca. 5 cm both sides sinuate upward to form a tube， petiole ca. 1 cm long， connected with stem by joints and resembles stem extension. Inflorescence racemes growing from axillary of leaves， terminal with clustered scape， but at the same time， only growing 1-2 racemes， each with 1 flower， scape with 3-4 sheaths at base， sheath trianglarovate， 1.5-1.7 × 1 cm， apex acuminate. Peduncle 1-1.2 cm long， with 1 tubular sheath at base， ca. 4 × 4.5 mm， apex acuminate. Flowers white， starshaped. Pedicel and ovary 9-10 mm long， densely hirsute. Floral bracts trianglar， 2-2.5 × 3-3.5 mm， apex acuminate. Sepals similar， lanceolate， hairy abaxially， base slightly densely， 12-13 × 4 mm， apex acute， 5vined， lateral sepals slightly shorter， mentum ca. 3 mm deep， 4 mm in diam.， apex bilobed; Petals 12-13 × 3 mm， linear lanceolate， narrowly acuminate towards apex， shorter than lateral sepals， 3veind; Lip ca. 15 mm long， 3lobed， sidelobes triangular ca. 3 × 1.2 mm， obtuse with finely hair margins; midlobe lanceolate with curved downwards， apex acute， disc with two ridges on the middle of sidelobes， base of the lip narrows into claws， claw ca. 5 mm long， bent and Fig. 1Ceratostylis radiata J. J. Sm. A. Habitat （with capsule）;

B， C， D， E. Flower （with different view）. （Photographed by Li Jianwu）

concealed in the mentum; Column ca. 1.2 mm long， column foot ca. 3 mm long， stelidia oblong， ca. 2 mm long， apex rounded; anther cap oblong; pollinia 8. Capsule ellipsoid， ca. 1.2 × 0.8 cm.

China. Tibet： Medog County， Linzhi City. It is epiphytic on semigreen forest beside the Yarlungzangbo River， alt. 1 077 m， November 2017. Flowering from November to December. Jin Xiaohua， Li Jianwu， Wang Xilong， Wang Chengwang 19116 （XZ！， PE?。?

Distribution： China （Tibet）， Vietnam， Myanmar， Fig. 2Bulbophyllum psychoon Rchb. f.? A. Habitat; B， C. Inflorescence. （Photographed by Li Jianwu）

Key characteristics to Ceratostylis1a. Leaves subterete， stem more than 20 cm， flowers yellowCeratostylis subulata

1b. Leaves linear to narrowly oblong; stem less than 10 cm， completely enclosed by sheaths.

2a. Stem branchingC. himalaica

2b. Stem unbranched.

3a. Leaves longer， 15-25 cm long， flowers whiteC. radiata

3b. Leaves shorter， 2.5-6.0 cm long， flowers white with purplered or purplish stripes.

4a. Stem ca. 1 cm， flower white with purplish stripes near baseC. hainanensis

4b. Stem ca. 0.2 cm， flower white with purplered spottedC. siamensis

Key characteristics to Bulbophyllum psychoon，? B. levinei， B. eublepharum

and B. insulsoides in section Desmosanthes

1a. Inflorescence umbellate

2a Petals ovatelanceolate， apex long acuminateBulbophyllum levinei

2b Petals ovate， apex obtuseB. psychoon

1b. Inflorescence racemose

3a. Lip 3.5-4 mm B. eublepharum

3b. Lip 2-2.8 mmB. insulsoides

India， Thailand， Malaysia， Java， Sumatra.

Ceratostylis radiata was published on Die Orchideen from Java in 1905. The type specimen from Herbarium catalogue of Kew was collected from Langkawi of Malaysia. After that， it was also found in Vietnam， Myanmar， India and Thailand （Seidenfaden， 1986; Kuezweil & Lwin， 2012; Odyuo et al.， 2013; Averyanov et al.， 2016）. This species was easily identified by its short stem 2-2.5 cm， pure white flower， lip 3lobed， starshaped without colored spot in the field.

格當(dāng)石豆蘭（新擬）Fig. 2

Bulbophyllum psychoon Rchb. f.， in Gard. Chron.， n. s. 10： 170-171. 1878.

Bulbophyllum Thouars （1822） is the largest genus in Orchidaceae （Chase et al.， 2015）. There are about 150 species in China （Zhou et al.， 2016）. We have identified this species as Bulbophyllum psychoon which belongs to section Desmosanthes. There are three species， Bulbophyllum levinei， B. eublepharum and B. insulsoides， distributing in China in this section （Chen et al.， 1999）.

Epiphytic herbs. Rhizomes creeping. Roots from rhizome nodes on base of pseudobulbs. Pseudobulbs subcylindric or bottleshaped， 5-10 × 2-4 mm， with a terminal leaf. Leaf blade narrowly oblong or obovatelanceolate， 3-4 × 0.5-0.7 cm， thinly leathery， base contracted into petiole，? Petiole 3-4 mm， margin slightly undulate， apex subacute. Scape arising from base of pseudobulb， erect， 6-8 cm， longer than leaves， glabrous. Inflorescence erect， shortened， umbellike， often 26flowered; peduncle ca. 4 mm， sparsely with 2 or 3 tubular sheaths; floral bracts erect， narrowly lanceolate， 2-3.5 mm， apex acuminate. Pedicel and ovary longer than floral bracts. Flowers white tinged with purple. Dorsal sepal ovatelanceolate， concave， 3-4 × 1.5-2 mm， abruptly contracted and thickened above middle， margin denticulate， apex acute; lateral sepals obliquely ovatelanceolate， 3-5 × 1.5-2 mm， thickened above middle， base adnate to column foot forming a mentum， margins entire， apex cuspidate. Petals connivent to sepals， ovate， ca. 2-2.5 × 1.5-2 mm， margins denticulate， apex obtuse. Lip recurved， lanceolate in outline， 2-2.5 mm， nearly fleshy， basal half grooved， base attached to end of column foot， immobile， margin entire， apex subacute; column ca. 1.2 mm， column foot curved， ca. 1.5 mm， with free part ca. 0.5 mm， stelidia filiform， ca. 0.5 mm; anther cap subglobose， apex narrowed and beaked， with a densely finely papillate ridge centrally.

China. Tibet： Medog County， Linzhi City. It is epiphytic on broadleafconiferous forest beside the road， alt. 1 769 m， November 2017. Flowering from November to December. Jin Xiaohua， Li Jianwu， Wang Xilong， Wang Chengwang 19192 （XZ！， PE！）.

Distribution： China （Tibet）， Vietnam， Laos， India.

Bulbophyllum psychoon Rchb. f. was first described and published on The Gardeners’ Chronicle by Reichenbach & Heinrich Gustav in 1878. After that， it was also found in Vietnam and Laos （Averyanov， 2007， 2013）. Bulbophyllum psychoon is similar to B. levinei， but this species was easily identified by its white tinged with purple flower， with shortened， umbellike inflorescence with 26flowered. Petals ovate， apex obtuse. Flowering from November to December.

Ceratostylis radiata and Bulbophyllum psychoon were collected in Medog County， Tibet， China and it confirmed the flora characteristics of Medog belonging to the tropical monsoon forests. According to researchers， overcollection and habitat destruction are the most threats to orchid species. To deal with these threats， we recommend the local government should prohibit illegal collection and strengthen the scientific management， strictly limit human access to the core area and buffer zone by the Yarlungzangbo Grand Canyon National Nature Reserve. Protected areas are the cornerstone of insitu conservation， protection of this rare and endangered orchids could be enhanced through the implementation of a management plan which included insitu or exsitu conservation and artificial cultivation. Discovery of this new record species of Orchidaceae further highlights the high value for biodiversity conservation of Southeastern of Tibet and calls for more comprehensive investigation on ecological surveys， studies， and environmental protection in this area. This report is only a small part of our current work. With the deepening of field investigations and the completion of indoor specimen identification， it is believed that there will be more new discoveries.

AcknowledgementsWe are grateful to Dr. Jin Xiaohua for his critical review of the manuscript， to Lhakpa Phuntsok， Kelsang for their kind help in the fieldwork.

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