Bulbophyllum, Adelopetalum, Lepanthanthe, Macrouris
Total Page:16
File Type:pdf, Size:1020Kb
A taxonomic revision of Bulbophyllum, sections Adelopetalum, Lepanthanthe, Macrouris, Pelma, Peltopus, and Uncifera (Orchidaceae) J.J. Vermeulen Rijkshcrbarium / Hortus Bolanicus, Leiden, The Netherlands (Drawings by the author) Contents Summary 2 1. Introduction 2 2. Taxonomic history ofBulbophyllum in Southeast Asia 3 3. Materials and methods 3 4. Species concept 4 5. Terminology 5 6. Notes the on morphology of Bulbophyllum! 5 7. A cladistic of the revised analysis sections 7 7.1. Introduction 7 7.2. The preferred computerprogram 8 7.3. Some aspects of the followed procedure 9 7.4. A priori assumptions for this analysis 13 7.5. The analyses 18 7.6. The phylogenetic relationship between the sections 43 7.7. Discussion 44 8. A biogcographical analysis of the revised sections 47 8.1. Introduction 47 8.2. Recognition ofareas of endemism in New Guinea 48 8.3. and blocks in and Coinciding species ranges geotectonic around New Guinea 54 8.4. Ad-hoc explanations regarding observed patterns 58 8.5. Areas of endemism elsewhere 60 9. Cultivation 60 10. Acknowledgements 61 11. References 62 12. Revisions— Bulbophyllum 64 the sections revised in this volume Key to 64 Section Adelopetalum' 66 Section Lepanthanthe 73 Section Macrouris 89 Section Pelma 121 SectionPeltopus 145 Section Uncifera< 176 13. Identification list 187 Legends to Figures 26-141 192 Figures 26-141 203 Index 319 Legends to the plates 323 Plates 1-6 Orchid Monographs 7 (1993) 1-324, figures 1-141 + plates 1-6 1 Summary A revision is presented of six sections of the genus Bulbophyllum (Orchidaceae): sect. Adelopetalum (mainly occurring in Australia), sect. Lepanthanthe, sect. Macrouris, sect. Pelma, sect. Peltopus, and sect. Uncifera (all mainly occurring in New Guinea). Together these include 110 species and 9 subspecies. Forty- are either described in this revision or in this re- seven species and 4 subspecies new; they are precursors to The reduced the well vision. genus Dactylorhynchus is to Bulbophyllum. Keys to species, as as synonymy, descriptions and illustrations of each species are provided. Some aspects of the morphology of the plants are discussed. A of each revised section is A method select the closest cladistic analysis given. to outgroup spe- cies from anumber of possibilities is developed;this method is applied here to hypothesize the phylogenetic relationships between the sections. A biogeographical analysis of the New Guinean species is attempted but because show observed resemblances between fails, most species overlapping ranges. Nevertheless, species and the outline of land which role in the of the island allow ranges masses played a geotectonic history a conjectural scenario for the evolutionary history of Bulbophyllum in the area. Key word's: Orchidaceae, Bulbophyllum, East Malesia, New Guinea, Australia, cladistics, biogeography. 1. Introduction In this volume a revision is presented of six sections of the genus Bulbophyllum (sub- tribeBulbophyllinae, tribe Epidendreae). Five of these mainly occur either in New Guinea, and in the surrounding archipelagos West, North and East of this island: sect. Lepanthan- the, sect. Macrouris, sect. Pelma, sect. Peltopus, and sect. Uncifera. The sixth, sect. Adelo- petalum is almost confined to Australia. The sections to be revised have been selected so that five of themshare an almost unique, albeit polythetic set ofcharacters (i.e. a set of characters occurring in a majority of the spe- cies of a group; see Geesink, 1987: 77) within Bulbophyllum: "inflorescence racemose; node between rachis and pedicel not in the axil of the subtending bract, but shifted in the directionof the flower." Elsewhere within Bulbophyllum this combination is found in of Intervallatae some New Guinean species sect. (sensu Vermeulen, 1991: 151; this section is distinct in having the polythetic character: one floweropen at a given time), in sect. Pachy- anthe from New Guinea (Schlechter, 1913: 750; characterized by large flowers with a ver- rucose lip), as well as in two Bornean species of sect. Hirtula: B. jolandae J.J. Vermeulen and B. rariflorum J.J. Smith (see Vermeulen, 1991). The species of the sixth section, sect. Peltopus, all have 1-flowered inflorescences. The section had to be added because it shares a numberof unique characters (foot ofthe column with a toothor a knob immediately above in which this with Pelma. the ligament; lip with a cavity at its base lump fits) sect. Presum- ably the two together constitute a monophyletic group. in The sections have also been selected such a way that a number ofthem can be regard- ed as monophyletic (because they have sets of unique characters), while the others are like- ly to contain the outgroup species of the monophyletic sections. The grouping of the New Guinean species into sections in this volume is derived from Schlechter (1913). Although Schlechter presented an admirably comprehensive enumera- tion of the hundreds of he found, his work falls short reliable foun- many new species as a dation for revisions for several reasons. Schlechter's sections are often based on a few characters which he regarded a priori as diagnostically important. He tended to pay much showed inclination less attention to other characters. He also an to exile aberrant species to sections the characters which would separate or even separate genera, overlooking justify 2 Orchid Monographs 7 (1993) their inclusion in existing sections. An example of this is Bulbophyllum latipes J.J. Smith off Schlechter the From the (sect. Pelma), which was split by as genus Dactylorhynchus. cladistic analysis (see Chapter 6) it appears that the unique characters of this species which caused its recognition as the type of a new genus, are better regarded as autapomorphies within sect. Pelmaof Bulbophyllum. Schlechter's methods of working also led to the mis- placement of a small percentage of his species. For the present revision, these 'stowaways' had to be tracked down. This was a time-consuming affair. It involved the analysis of a large numberof type specimens, because characters now considered to be diagnostic, but not observed by Schlechter, did not feature in the original species descriptions. A good source of misplaced species proved to be Schlechter's sections Cycloglossum and Micro- monanthe, both containing species which he couldnot includeelsewhere. Schlechter also arranged his sections into subgenera, thus suggesting phylogenetic rela- hierarchical of the sections ofBul- tions between sections. I prefer to postpone a grouping nomenclatural until bophyllum, with its possibly ensuing consequences, estimated phylo- genetic relationships between all the sections are available, inferred from cladistic analysis. This will only be possible after revision of the entire genus. 2. TAXONOMIC HISTORY OF BULBOPHYLLUM IN SOUTHEAST ASIA The generic name Bulbophyllum was first used by Du Petit Thouars (1822). At a later date it was conserved against an older name (see Vermeulen, 1987: 2). The East Malesian of the remained unknown the nineteenth in the species genus largely during century. Only first decades of the twentieth century, adventurous botanists started exploring the interior of Guinea. discovered almost wealth of New They an unequalled orchid species, among which they found hundreds of species of Bulbophyllum. The documentationof this cornucopia was mainly the work of threetaxonomists: H.N. Ridley (1916), R. Schlechter (1911-1914) and J.J. Smith continued in least of the (1911-1935). Although some collecting at a part area after the Second World War, the taxonomic work was not taken up again. The above mentionedauthors all preferred to keep Bulbophyllum as a single, extremely speciose genus. Only comparatively small groups have been split off as separate genera. Their generic status is disputed (see, for instance, Seidenfaden, 1973). In this volume the monotypic genus Dactylorhynchus Schltr. has been included in a section of Bulbophyllum. 3. MATERIALS AND METHODS Materials — This revision is partly based on the herbarium specimens and liquid-pre- served samples already stored in a number of institutions. In addition, a large number of specimens (approx. 3000 spirit samples of Bulbophyllum species from all over the world in some 10 years) have been collected especially for the revision of the genus, either by persons living in countries where the genus is native, or by persons or institutions growing the plants. These newly acquired collections have added much information to the revision because of their oftenexcellent quality and completeness. Preparation ofthe materials and the plates — A spirit sample was analyzed ofeach spe- cies well make sketches. All other to survey the characters, as as to analytical spirit samples as well as the herbarium material were compared with these samples. Where no spirit Orchid Monographs 7 (1993) 3 material was available of a species, a first analysis was based on an herbarium specimen of which flowers were soaked in water, methylated spirit, ammonia or a NaOH-solution. Precautions were taken not to cause unnecessary damage to the material, particularly solvents. A flower boiled when using the latter two very aggressive was always in water due the first. Then, all the flowerparts sticking together to drying process were gently prised The flower then in if this in hot alka- apart. was only soaked spirit and, was not effective, a marie' line solution. This was preferably done 'au bain (in a larger vessel containing water) which would the flower. If flowers to prevent boiling, destroy were selected which were properly dried (quickly, without moulding or decaying, and without excessive flattening) recovered their natural reasonable the flowerparts shape up to a extent. the of the flowers and the floral have been Generally, drawings parts prepared with a Wild stereo microscope with a 'camera lucida' device. Ample corrections were almost always necessary because of distortion or oblique flattening, irrespectively whether the flowers were examinedfresh, pickled in spirit, or as boiled herbariummaterial. Preparation of the revision — Compared to the revision of the Continental African Bul- bophyllinae (Vermeulen, 1987), the revision presented in this volume is much more con- cise.