孟連苞葉蘭蘭科的重新發現與形態特征增補

王雨芊 劉強 吳訓鋒 李金龍 王博軼 潘博

摘 要： 孟連苞葉蘭（Brachycorythis menglianensis）自2001年發表以來，再也沒有被發現和記錄過。由于能夠用于分類學參考的僅為模式標本和依據標本繪制的素描圖，加之原始文獻的描述不夠細致，以致于HenrikPedersen將其作為長葉苞葉蘭（B. henryi）的異名處理。時隔十五年后，我們在該種的模式產地進行野外蘭科植物考察時，有幸重新發現了該種。通過對其新鮮帶花植株的詳細比對之后，發現孟連苞葉蘭與長葉苞葉蘭在形態上具有明顯的差異，如孟連苞葉蘭葉片卵圓形，葉片大小（2.5- 4.7 × 1.7-2.3 cm）、唇瓣密被疣狀突起且先端缺刻或2裂等特征，明顯有別于長葉苞葉蘭。因此，在該研究中支持孟連苞葉蘭的分類學地位，同時對該種的形態特征、生境以及生存現狀等信息進行了增補。

關鍵詞： 孟連苞葉蘭， 蘭科， 重新發現， 形態特征增補， 瀕危狀況評估

Genus Brachycorythis was proposed by Lindley in 1838， which was characterized by the structure of the leaf-like bracts， labellum（especially the inflated base or hypochile， with which Lindley compared with similar structure in the genus Stanhopea）and the bluntly galeate perianth. It was represented by about 35 species and mainly occurring in South tropical African and Madagascar， with a few species extending to tropical and subtropical Asia（Seidenfaden， 1977; Pridgeon et al.， 2001）. Only three species were reported from China， of which just one species was believed to be endemic（Qian， 2001， Pridgeon et al.， 2001; Chen et al.， 2009）.

Brachycorythis menglianensis Y. Y. Qian is an interesting species collected from Menglian County. As far as we can tell， there have been no subsequent collections of this species since 2001（Qian， 2001）. Until now， it has been only known from the illustration and type specimen. In addition， the type specimen is poorly preserved and appears to be severely shrunk， the key characteristics are hard to diagnose. The plant figured and described by Qian was not detailed and accurate. Sometimes it was even be considered as the synonym of B. henryi（Pedersen， 2010）. During recent field work in the Menglian County in South Yunnan in 2014， an unusual species of Brachycorythis was discovered. After a comprehensive review of literature and herbarium specimens， we finally confirmed that our collection match the little-known B. menglianensis. It was similar with B. henryi， but differed by floral bract as long as pedicel and ovary， labellum densely papillate adaxially and apex of labellum emarginated or 2-lobe（Qian， 2001; Chen et al.， 2009）. Based on the material recently collected， we hereby present an updated description， along with color plates to facilitate its recognition.

Taxonomy

Brachycorythis menglianensis Y. Y. Qian in Acta Phytotax. Sin. 39： 278. 2001. 孟連苞葉蘭（Fig. 1，2）

Type： CHINA. Yunnan Province， Menglian County， in grassland， 1 600 m， 3 July 1993， Y. Y. Qian 2902（Holotype， PE！）Terrestrial. Plants ca. 41 cm tall. Tuber ellipsoid， 3.6 cm long， 2.4 cm in diam. Stem erect， with 2-3 sheaths at base， sparsely 5 or 6-leaved above. Leaves ovate，（25.38-46.79）mm long，（17.46-22.63）mm wide， apex acute， without petiole， base amplexicaul. Inflorescence with 4-5 well-spaced flowers; floral bracts leaf-like， slightly smaller than leaves. Flowers white， marked with purple-red， lip purple; pedicel and ovary slightly arching toward apex， twisted， cylindric， slightly pubescent along ridges， ca.（18.74 ± 1.21）mm long; dorsal sepal narrowly ovate，（16.06 ± 0.35）mm long，（5.68 ± 0.45）mm wide， 3-veined， apex obtuse; lateral sepals oblique-ovate，（17.06 ± 0.66）mm long，（5.40 ± 0.25）mm wide， 3-veined， apex obtuse. Petals lanceolate，（14.07 ± 0.64）mm long，（3.16 ± 0.13）mm wide， 1-veined， apex obtuse; lip much larger than sepals and petals， suborbicular，（23.39 ± 2.04）mm long，（28.56 ± 0.35）mm wide， densely with deeply purple stripes on the center of lip; spur white， sub-cylindrical， slightly wider towards the obtuse apex， densely pubescent at the entrance of spur，（12.94 ± 0.83）mm long，（3.67 ± 0.25）mm wide， bifid at apex; column short，（4.14 ± 0.43）mm. Pollinia 2， granular-farinaceous，（3.98 ± 0.13）mm long. Flowering： June to July.

Distribution and habitat： Until now， Brachycorythis menglianensis had only been found in a single population

A. Front view of flower; B. Lateral view of flower; C. Front view of column; D. Each part of flower; E. Vertical section of spur; F. Front and lateral view of Pollinia; G. Tuber and roots; H. Plant. All drawn by B. Pan from the Qiang Liu 203（holotype， HITBC）.

Fig. 1 Brachycorythis menglianensis

of about 20 plants in the Menglian County， South Yunnan， China. It occurs in the subtropical monsoon evergreen broad-leaved forest at an elevation of ca. 1 560 m. The dominant species are Trigonobalanus

A. Habitat; B. Plant; C. Tuber and roots; D. Front view of flower; E. Spur; F. Each part of flower; G. Pollinia; H. Front view of column（Photographed by Qing Liu）.

Fig. 2 Brachycorythis menglianensis

doichangensis（A. Camus）Farman， Schima wallichii Choisy， Castanopsis delavayi Franchet，? Castanopsis fleuryi Hickel & A. Camus， Betula alnoides Buchanan-Hamilton ex D. Don. Some other orchids are also found in the area， such as Habenaria malintana（Blanco）Merrill， Pecteilis susannae（Linnaeus）Rafinesque， Anthogonium gracile Lindley，? Habenaria reniformis（D. Don）J. D. Hooker and Nervilia crociformis（Zollinger & Moritzi）Seidenfaden.

Conservation status： Brachycorythis menglianensis is endemic to China and just one population with about 20 plants had been found until now. The habitat was outside the natural reserve and frequently disturbed by the flocks and herds. Additionally， it is also collected as Habenaria spp. for medicine by local people. Therefore， it is considered as critically endangered（CR）according to IUCN red list criteria（IUCN， 2017）.

Specimen examined： China. Yunnan Province. Menglian County， Mengma Town， under the open monsoon evergreen broad-leaved forest， 1 560 m， 20 June 2015， Qiang Liu 203（HITBC！）

Taxonomic notes： Only the specimen and illustration of this species previously existed on which the protologue was based（Qian， 2001）. Plant and flowers characteristics were not described in enough details in the original description， and led to be treated as the synonym of B. henryi by Pedersen（2010）. After the comprehensive observe plant and flower characters using the fresh materials， we found that B. menglianensis significantly differed from B. henryi by having smaller size leaf（2.5-4.7 × 1.7-2.3 cm）， floral bract as long as pedicel and ovary， labellum densely papillate adaxially and apex emarginated or 2-lobe， and apex of spur obviously 2-lobed（Chen et al.， 2009）. So， we still believe that B. menglianensis should be supported as distinct from B. henryi. Additionally， B. menglianensis is similar to B. galeandra， but the latter has the small size of flowers and short， undivided spur（Chen et al.， 2009）（more detail information see Table 1）.

Table 1 Morphological comparison of Brachycorythis menglianensis and related species

CHEN SC， STEPHAN WG， PHILLIP JC， 2009. Brachycorythis [M]// WU ZY， RAVEN PH， HONG DY， Flora of China. Beijing： Science Press; St. Louis： Missouri Botanical Garden Press： 100-101.

IUCN Species Survival Commission， 2017. IUCN red list categories and Criteria， Version 3.1. [M]. United Kingdom： IUCN， Gland， Switzerland and Cambridge.

PEDERSEN H， 2010. Species delimitation and recognition in the Brachycorythis helferi complex（Orchidaceae）resolved by multivariate morphometric analysis [J]. Bot J Linn Soc， 162： 64-76.

PRIDGEON A， CRIBB P， CHASE M， et al.，2001. Brachycorythis [M]//Genera Orchidacearum： Vol. 2： Orchidiodeae（Part I）. Oxford： Oxford University Press： 265-269.

QIAN YY， 2001. A new species of Brachycorythis Lindl.（Orchidaceae）from Yunnan， China. [J]. Acta Phytotax Sin， 39（3）： 278-279.

SEIDENFADEN G， 1977. Brachycorythis Lindl. [M]// Orchid genera in Thailand Ⅴ. Dansk Botanisk Arkiv， Copenhagen： 9-15.

（責任編輯 何永艷）