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Bulbophyllum is a genus of mostly epiphytic and lithophytic orchids in the family Orchidaceae. It is the largest genus in the orchid family and one of the largest genera of flowering plants with more than 2,000 species, exceeded in number only by Astragalus. These orchids are found in diverse habitats throughout most of the warmer parts of the world including Africa, southern Asia, Latin America, the West Indies, and various islands in the Indian and Pacific Oceans.[2] Orchids in this genus have thread-like or fibrous roots that creep over the surface of trees or rocks or hang from branches. The stem is divided into a rhizome and a pseudobulb, a feature that distinguished this genus from Dendrobium. There is usually only a single leaf at the top of the pseudobulb and from one to a large number of flowers are arranged along an unbranched flowering stem that arises from the base of the pseudobulb. Several attempts have been made to separate Bulbophyllum into smaller genera, but most have not been accepted by the World Checklist of Selected Plant Families.

Bulbophyllum
Bulbophyllum echinolabium.jpg
Bulbophyllum echinolabium
Scientific classification edit
Kingdom: Plantae
Clade: Angiosperms
Clade: Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Epidendroideae
Tribe: Dendrobieae
Subtribe: Bulbophyllinae
Genus: Bulbophyllum
Thouars, 1822[1]
Species

See List of Bulbophyllum species

Diversity
1805 species
Synonyms[1]
List of synonyms
  • Adelopetalum Fitzg. 1891.
  • Anisopetalum Hkr. 1825.
  • Blepharochilum M.A.Clem. & D.L.Jones 2002
  • Bolbophyllaria Rchb.f 1852.
  • Bolbophyllopsis Rchb.f. 1852.
  • Bolbophyllum Spreng. 1826.
  • Canacorchis Guillaumin 1964
  • Carparomorchis M.A.Clem. & D.L.Jones 2002
  • Cirrhopetalum Lindl. 1830
  • Cochlia Bl. 1825.
  • Codonosiphon Schltr. 1913.
  • Dactylorhynchus Schltr. 1913
  • Didactyle Lindley 1852.
  • Diphyes Bl. 1825.
  • Ephippium Blume 1825.
  • Epicranthes Bl. 1825.
  • Epicrianthes Bl. 1828.
  • Ferruminaria Garay, Hamer & Siegerist 1994
  • Fruticicola (Schltr.) M.A.Clem. & D.L.Jones 2002
  • Gersinia Neraud. 1826.
  • Hamularia Aver. & Averyanova 2006
  • Hapalochilus (Schltr.) Senghas 1978
  • Henosis Hkr.f 1890.
  • Hippoglossum Breda 1829
  • Hordeanthos Szlach. 2007
  • Hyalosema Rolfe 1919
  • Ichthyostomum D.L.Jones, M.A.Clem. & Molloy 2002
  • Katherinea A. D. Hawkes 1956.
  • Kaurorchis D.L.Jones & M.A.Clem. 2002
  • Lepanthanthe (Schltr.) Szlach. 2007
  • Lyraea Lindl. 1830.
  • Macrolepis A. Rich. 1834.
  • Malachadenia Lindley 1839.
  • Mastigion Garay, Hamer & Siegerist 1994
  • Megaclinium Lindley 1826.
  • Monosepalum Schltr. 1913
  • Odontostyles Breda 1827.
  • Oncophyllum D.L.Jones & M.A.Clem. 2001
  • Osyricera Bl. 1825.
  • Oxysepala Wight 1851.
  • Pachyrhachis A.Rich. 1845
  • Papulipetalum (Schltr.) M.A.Clem. & D.L.Jones 2002
  • Pelma Finet 1909
  • Peltopus (Schltr.) Szlach. & Marg. 2001
  • Phyllorchis Thou. 1822.
  • Rhytionanthos Garay, Hamer & Siegerist 1994
  • Sarcobodium Beer 1854
  • Sarcopodium Lindley & Paxton 1850.
  • Serpenticaulis M.A.Clem. & D.L.Jones 2002
  • Sestochilos Breda 1828.
  • Spilorchis D.L.Jones & M.A.Clem. 2005
  • Sunipia Lindley 1826.
  • Synarmosepalum Garay, Hamer & Siegerist 1994
  • Tapeinoglossum Schltr. 1913
  • Taurostalix Rchb.f. 1852.
  • Trachyrhachis (Schltr.) Szlach. 2007
  • Tribrachia Lindley 1824.
  • Tripudianthes (Seidenf.) Szlach. & Kras 2007
  • Vesicisepalum (J.J.Sm.) Garay, Hamer & Siegerist 1994
  • Xiphizusa Rchb.f 1852.
  • Zygoglossum Reinw. 1826 [1828].

Contents

DescriptionEdit

Plants in the genus bulbophyllum are epiphytic or lithophytic sympodial herbs with thread-like or fibrous roots that creep over the surface on which they grow. The stem consists of a rhizome and a pseudobulb, the latter with one or two usually fleshy or leathery leaves. The flowers are arranged on an unbranched raceme that emerges from the pseudobulb, usually from its base. The dorsal sepal is free from the lateral sepals which themselves may be free or fused to each other. The petals are also free from each other and smaller than the lateral sepals. The labellum is often fleshy, curved and hinged to the base of the column.[1][3][4][5]

Taxonomy and namingEdit

The genus Bulbophyllum was first formally described in 1822 by Louis-Marie Aubert du Petit-Thouars in his book Histoire particulière des plantes orchidées recueillies sur les trois Iles Australes d’Afrique, de France, de Bourbon et de Madagascar in which he described eighteen species of Bulbophyllum.[1][6]

There are now more than 2,800 records (accepted names and synonyms) for this genus. This large number and the great variety of its forms make the genus a considerable challenge for taxonomists: 120 sections and subgenera have been listed.[5]

The genus name (Bulbophyllum) is derived from the Ancient Greek words bolbos meaning "a fleshy, usually underground, stem or bud"[7]:773 and phyllon meaning "leaf",[7]:605 referring to the pseudobulbs on top of which the leaf grows.[5]

Distribution and habitatEdit

The center of diversity of this genus is in the montane forests of Papua New Guinea (more than 600 species) which seems to be the evolutionary homeland,[8] though the genus is pantropical and widespread, occurring in Australia, Southeast Asia (with over 200 species in Borneo), India, Madagascar (with 135 species, some endemic), Africa and in tropical central and South America.[5]

The erect to pendent inflorescence arises laterally from the base of the pseudobulb. The flower form has a basic structural blueprint that serves to identify this genus. But this form can be very diverse : compound or single, with few to many flowers, with the resupinate flowers arranged spirally or in two vertical ranks. The sepals and the petals can also be very varied : straight or turned down, without footstalk or with a long claw at the base. They are often hairy or callous. There are two to four hard and waxy pollinia with stipes present or absent. The fruits are beakless capsules.[5]

EcologyEdit

PollinationEdit

Many Bulbophyllum species have the typical odor of rotting carcasses, and the flies they attract assist in their reproduction through pollination.[5] Nevertheless, there are many species with mild and pleasant floral fragrance attract fruit flies (particularly Bactrocera spp.) via methyl eugenol, raspberry ketone or zingerone that also acts as floral reward during pollination.[9][10][11][12]

Use in horticultureEdit

The fabulous and bizarre species that compose this large genus have been the focus of orchid collectors for over a century. The plants require high humidity combined with good air movement and most of them are ever-blooming - flowering continuously throughout the year. They grow best at moderate light levels, but do not in deep shade. They are considered moderate-to-difficult to cultivate, and require a controlled growing environment to achieve some degree of success. They are not typically suitable as houseplants, and most will not thrive in a Wardian case unless they receive adequate air movement.

The plants' growth habit produces widely spaced pseudobulbs along cord-like rhizome sections, and most of these plants are best accommodated on plaques. Some species in this genus can get very large, but most are small to medium-sized epiphytes from warm, moist, humid tropical forests. They can grow continuously year round with no apparent dormancy period if they are kept warm, are moderate feeders in cultivation, and must be kept moist all the time. They can tolerate dryness for short periods, but they have fine root systems which require moist conditions all the time.[13]

Some of the smaller species do well in pots with small-diameter bark substrate. The plants produce very fine roots generally, and the roots are easily damaged. The plants react poorly to disturbance of their roots. They are easy to maintain once a good environment is established with high humidity and a fresh, buoyant, lightly circulating atmosphere being critical. Most of these species cannot tolerate cold temperatures or freezing.[13]

The flowers produce various odors resembling sap, urine, blood, dung, carrion, and, in some species, fragrant fruity aromas. Most are fly-pollinated, and attract hordes of flies. Bulbophyllum beccarii in bloom has been likened to smelling like a herd of dead elephants and both this species and Bulbophyllum fletcherianum are variously described as making it difficult to walk into a greenhouse in which they are being cultivated if the plants are in bloom because of their overpowering floral odors.[13]

SpeciesEdit

Some species are known for their extreme vegetative and floral forms:

New species are being discovered every year, such as:

There is one intergeneric hybrid : Triasphyllum (abbr.: Tphm.) (Bulbophyllum x Trias)

Other selected species include:

Conservation statusEdit

A number of Bulbophyllum species are threatened with extinction, and are recognised as such by the World Conservation Union (IUCN):

Additionally, Bulbophyllum porphyrostachys is listed as near threatened.

GalleryEdit

ReferencesEdit

  1. ^ a b c d "Bulbophyllum". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew.
  2. ^ David G. Frodin (2004). "History and concepts of big plant genera". Taxon. 53 (3): 753–776. doi:10.2307/4135449. JSTOR 4135449.
  3. ^ Weston, Peter H. "Genus Bulbophyllum". Royal Botanic Garden Sydney. Retrieved 5 December 2018.
  4. ^ "Bulbophyllum". Australian National Botanic Gardens. Retrieved 5 December 2018.
  5. ^ a b c d e f The Orchids, Natural History and Classification, Robert L. Dressler. ISBN 0-674-87526-5
  6. ^ Thouars, Louis-Marie (1822). Histoire particulière des plantes orchidées recueillies sur les trois Iles Australes d’Afrique, de France, de Bourbon et de Madagascar. Paris. pp. 93–110. Retrieved 5 December 2018.
  7. ^ a b Brown, Roland Wilbur (1956). The Composition of Scientific Words. Washington, D.C.: Smithsonian Institution Press.
  8. ^ Emly S. Siegerist (2001). Bulbophyllums and their allies: a grower's guide. Portland (OR): Timber Press. ISBN 978-0-88192-506-7.
  9. ^ Tan, K.H. & Nishida, R. (2000) Mutual reproductive benefits between a wild orchid, Bulbophyllum patens, and Bactrocera fruit flies via a floral synomone.Journal of Chemical Ecology 26: 533-546.
  10. ^ Tan, K.H. & Nishida, R. (2005) Synomone or Kairomone? - Bulbophyllum apertum (Orchidaceae) flower releases raspberry ketone to attract Bactrocera fruit flies.Journal of Chemical Ecology 31: 497-507.
  11. ^ Tan, K.H., Tan, L.T. & R.Nishida (2006) Floral phenylpropanoid cocktail and architecture of Bulbophyllum vinaceum orchid in attracting fruit flies for pollination. Journal of Chemical Ecology 32: 2429-2441.
  12. ^ Tan, K.H. (2009) Fruit fly pests as pollinators of wild orchids.Orchid Digest 73(3): 180-187.
  13. ^ a b c Illustrated Encyclopedia of Orchids ISBN 0-88192-267-6
  14. ^ André Schuiteman; Jaap Jan Vermeulen; Ed de Vogel & Art Vogel (2011). "Nocturne for an unknown pollinator: first description of a night-flowering orchid (Bulbophyllum nocturnum)". Botanical Journal of the Linnean Society. 167 (3): 344–350. doi:10.1111/j.1095-8339.2011.01183.x.
  15. ^ Mark Kinver & Victoria Gill (November 22, 2011). "Botanists discover 'remarkable' night-flowering orchid". BBC News.

BibliographyEdit

  • J.J. Vermeulen : Orchid Monographs Vol. 7 (1993), A taxonomic revision of Bulbophyllum, sections Adelopetalum, Lepanthanthe, Macrouris, Pelma, Peltopus, and Uncifera (Orchidaceae). iv + 324 pp., 25 text-figs. + 116 full-page line drawings, 6 pp. colour plates. ISBN 90-71236-17-X
  • Siegerist E.S.: - Bulbophyllums and their allies Timber Press, 2001, 77 colour photos, 296 pp ISBN 0-88192-506-3 - devoted solely to Bulbophyllums, it is an introductory guide for amateur and advanced orchid growers.

External linksEdit