Leonid V. Averyanov, Nong Van Duy, Nguyen Hoang Tuan, Maxim S. Nuraliev, Tatiana V. Maisak & Nguyen Cong Anh
Bulbophyllum cariniflorum var. orlovii Photo: N. Orlov
Bulbophyllum sonii Photo: N. X. Son
Bulbophyllum ustulata Photo: N. Orlov
Bulbophyllum flavescens Photo: N. Orlov
Bulbophyllum physocoryphum Photo: N. Nuraliev
Bulbophyllum ovatum Photo: L. Averyanov
Bulbophyllum wendlandianum Photos: N.H. Tuan
Abstract: Three taxa, Bulbophyllum cariniflorum var. orlovii (sect. Pleiophyllum), Bulbophyllum sonii (sect. Anisopetalon) and Bulbophyllum ustulata (sect. Brachystachya) are described as new for science. All of these novelties are local endemics of Vietnam. Additionally, four species, Bulbophyllum flavescens (sect. Aphanobulbon), Bulbophyllum ovatum (sect. Desmosanthes), Bulbophyllum physocoryphum (sect. Macrocaulia) and Bulbophyllum wendlandianum (sect. Cirrhopetalum) are recorded for the flora of Vietnam for the first time. These species are endemic of the Indochinese Peninsula in a broad sense, except for Bulbophyllum flavescens having wide distribution in western Malesia. Data on ecology, phenology, distribution, brief relevant taxonomic notes, as well as colour photographs and line drawings of the type and voucher specimens are provided for all reported taxa. Lectotypification is provided for Bulbophyllum wendlandianum.
Bulbophyllum cariniflorum has for a long time been taxonomically placed into a rather formal artificial group of deviated Bulbophyllum species known as a B. section Pleiophyllum (Seidenfaden, 1979; Pearce & Cribb, 2002; Chen et al. 2009). All these species have more or less similar 2-leaved pseudobulbs that is quite unusual for the genus. Meanwhile, species of this section show hardly close relations. At least B. cariniflorum and its close allies, such as B. triste Reichenbach (1861: 253) and B. viridiflorum (Hooker 1890: 779) Schlechter (1910: 108) look much more close to some members of B. sect. Anisopetalon (Hooker 1825: tab. 149) Lindley (1846: 181) according to their floral morphology. Our plant undoubtedly belongs to this group and most close to B. cariniflorum distributed mainly in the Himalayas. However, it distinctly differs from other known specimens of this species in such morphological details as large, slightly flattened, often 3-leaved pseudobulbs (1.8)2.5–3.0(3.4) cm tall and wide (vs. 2-leaved ovoid pseudobulbs 1–1.5 cm tall), large leaves (10)12–18(20) cm long (vs. 12–15 cm long), long panicle (2.0)3.0–5.0(6.5) cm long (vs. 2–3 cm long), narrowly ovate floral bracts (vs. narrowly lanceolate) and falcate, back curved stelidia (vs. straight erect subulate stelidia). Described variety belongs to species newly recorded in the flora of Vietnam. The discovery of our plant in Vietnam essentially extends the known species distribution area to the East and represents its first record in eastern Indochina.
Bulbophyllum sonii belongs to the rather formal group of species with simple lip (having no auricles or any other ornamentation) belonging to B. sect. Anisopetalon (= Racemosae). Bulbophyllum brevispicatum Z.H.Tsi & S.C.Chen (1994: 555) and B. triviale Seidenfaden (1979: 111) are probably most close to our plant. Some species with auriculate lip, e.g. B. allenkerrii Seidenfaden (1979: 112) and B. bittnerianum Schleichter (1910: 108), also show certain similarity with the new species. Our plant strikingly differs from all more or less similar known species in its dwarf habit, pendulous inflorescence, twice smaller flowers and curious setose hairiness on abaxial surface of sepals consisting of white dense papillous hairs.
Bulbophyllum ustulata belongs to B. sect. Brachystachya (= B. sect. Globiceps ) and is allied to some Himalayan taxa, namely Bulbophyllum conchiferum Reichenbach (1861: 253), B. cylindraceum Lindley (1830: 53) and B. khasyanum Griffith (1851: 284). Similarly, to these species, our plant possesses very small pseudobulbs, elongate, nodding, spadix-like, dense inflorescence with small sessile, flattened, overlapping flowers densely appressed to rather fleshy rachis. Meanwhile, the discovered plant cannot be identified as any of the above-mentioned species. Among the mentioned species, the new species may be most close to B. conchiferum undeservedly regarded as a synonym of B. khasyanum (Pearce & Cribb 2002), which type specimen has short, almost head-like spike. Inflorescence and flowers of B. ustulata fits well the excellent analytical drawing presented on type herbarium specimen of B. conchiferum stored at K [K000894441] in elongate rachis, dense, shell-like sessile flowers, acuminate, revolute apex of median sepal, acuminate recurved petals, 2-keeled lip and long stelidia. However, our plant differs from B. conchiferum in large involucral sheathing bract at the base of rachis (a feature that is also observed in typical samples of B. cylindraceum), glandular hairy median sepal, straight stelidia (vs. stelidia at the middle upward bent) and fleshy inflated margin of stigma close to the base of column foot. The new species was collected in a single location near summit of Phu Xai Lai Leng Mountain very close to the Laotian border.
The discovery of Bulbophyllum flavescens (Blume) Lindl. previously believed to be a Malesian endemic in northern Vietnam is remarkable and unexpected. The newly discovered quite isolated location expands known distribution area of this species almost 2000 km in northwestern direction and illustrates well the connection of Malesian flora with marginal tropical floras of mainland Asia. At the same time, the discovered Indochinese population certainly possesses relict nature and surely represents ancient geographical isolation resulted in some morphological divergence. The studied Vietnamese plants well differ from quite variable specimens described in details from the main area of the species distribution (Comber 1990, 2001, Seidenfaden & Wood 1992) in larger flowers with sepals 13–15 mm long (vs. sepals 6–8 mm long in Peninsular Malaysia and 10–11 mm long in Sumatra and Java) and narrowly lanceolate leaves 1.6–2 cm wide (vs. broadly lanceolate leaves 2–3 mm wide). In this connection, our plants probably represent a separate variety and need additional studies.
The specimens of Bulbophyllum ovatum Seidenfaden look identical with the species described from southern Thailand (Seidenfaden 1979) and initially regarded as local endemic of the Malay Peninsula. The population of this species discovered in northern Vietnam is distant from locus classicus at more than 1200 km in NNE direction.
Recent discovery of Bulbophyllum physocoryphum Seidenfaden in southern Vietnam and in Cambodia (Averyanov et al. 2016a) provides evidence of its much border distribution in southern Indochina than it was expected before.
The present discovery extends known distribution area of Bulbophyllum wendlandianum to almost 1000 km in SE direction and adds one more eastern Himalayan species to the flora of Vietnam. There are few doubts that this rare species may also be found in northern Laos. This species may be regarded as a true endemic of northern Indochina. Type herbarium material of B. wendlandianum was most likely destroyed or lost: “I do not know if a type specimen of Kränzlin’s plant exists, ...” (Seidenfaden 1972). Hence, the drawing which was probably based on the original material is designated here as a lectotype.
Note(b.info): Following G.A. Fischer & Vermeuelen 2014 and Vermeulen et al. 2014, B. cariniflorum v. orlovii belogns to sect. Lemniscata, B. sonii to sect. Racemosae, B. flavescens to sect. Stachysanthes and B. wendlandianum to sect. Cirrhopetaloides.
Published in Phytotaxa 369 (1): 1 - 14