Cytological studies on the genus Holcoglossum (Orchidaceae)

The karyotypes of ten species of Holcoglossum (Orchidaceae), a highly endangered and diversified genus from China, were investigated to study the infrageneric relationships, biogeography, and speciation patterns in the Hengduan Mountains. The karyotype formulae of the studied species are as follows: 2 n  = 38 = 20m + 18sm in H. subulifolium , 2 n  = 38 = 22m + 16sm in H. amesianum , 2 n  = 38 = 26m + 12sm (6 SAT) in H. lingulatum , 2 n  = 38 = 26m + 12sm in H. wangii , 2 n  = 38 = 10m + 28sm in H. kimballianum , 2 n  = 38 = 14m + 22sm + 2st in H. flavescens , 2 n  = 38 = 24m + 12sm + 2st in H. rupestre , 2 n  = 38 = 14m + 20sm + 4st in H. sinicum , 2 n  = 38 = 16m + 14sm + 8st in H. weixiense , and 2 n  = 76 in H. tsii . The karyotypes of two tropical species, H. amesianum and H. subulifolium , are the most primitive in the genus, whereas those of four temperate alpine species, H. sinicum , H. rupestre , H. weixiense , and H. flavescens , are more advanced. H. tsii is a tetraploid and H. rupestr e may be one of its ancestors. The low frequency of polyploidy in Holcoglossum in the Hengduan Mountains region supports the conclusion that chromosome stasis during rapid speciation is common there.  © 2007 The Linnean Society of London. Botanical Journal of the Linnean Society , 2007, 154 , 283–288.     

耳唇槽舌兰——中国兰科一新种

对产于云南的兰科新种耳唇槽舌兰(Hotcoglossum auriculatum)进行了描述和绘图。该新种具有显著特征：萼片与花瓣基部有长爪;花瓣边缘具不规则齿或呈啮蚀状;唇瓣椭圆状圆形,边缘有短流苏或啮蚀状流苏,基部有爪和耳,极易区别于该属已知的种类,包括它的近缘种白唇槽舌兰(H．subulifolium)。     

Generic delimitation and a new infrageneric system in the genus Holcoglossum (Orchidaceae: Aeridinae)

Based on herbarium and field observations, we confirm the generic delimitation of Holcoglossum and present a new infrageneric system for the genus. Our work supports Holcoglossum as a natural group including H. amesianum (Rchb.f.) Christenson and H. subulifolium (Rchb.f.) Christenson. The new infrageneric system of Holcoglossum includes two subgenera: Holcoglossum subgen. Brachycentron subgen. nov. and Holcoglossum subgen. Holcoglossum , the latter comprising two new sections, Holcoglossum sect. Holcoglossum and Holcoglossum sect. Sorotylos .  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 465–468.     

DNA barcoding of the recently evolved genus Holcoglossum (Orchidaceae: Aeridinae): a test of DNA barcode candidates

Orchidaceae is one of the largest families of flowering plants. Many species of orchid are endangered, and all species are included in Conventions on International Trade of Endangered Species of Fauna and Flora (CITES) I and II, but it is very difficult to identify orchid species, even those with fertile parts. The genus Holcoglossum (Orchidaceae: Aeridinae) has long been problematic in taxonomy. It consists of both long-evolved and radiated species and is an excellent case to use for testing DNA barcodes for Orchidaceae. We investigated the power of a subset of proposed plant barcoding loci [rbcL, matK, atpF-atpH, psbK-psbI, trnH-psbA and internal transcribed spacer (ITS)] to discriminate between species in this genus. Our results showed that all these DNA regions, except psbK-psbI and atpF-atpH, can be amplified easily from Holcoglossum and sequenced with established primers. The DNA regions matK and ITS had the highest variability. Among the six loci, matK resolved eight of the 12 Holcoglossum species and had the highest discriminatory ability. However, the combination of matK and ITS showed a greater ability to identify species than matK alone. Single or combined DNA markers discriminated between Holcoglossum species distributed in tropical areas effectively, but had less ability to identify radiated species from the temperate Hengduan Mountains of China. In the study, matK proved to be a useful DNA barcode for the genus Holcoglossum; however, complementary DNA regions are still required to accelerate the investigation and preservation of radiated species of orchid.     

Systematic Significance of Leaf Epidermal Features in Holcoglossum (Orchidaceae)

Determining the generic delimitations within Aeridinae has been a significant issue in the taxonomy of Orchidaceae, and Holcoglossum is a typical case. We investigated the phylogenetic utility of the morphological traits of leaf epidermis in the taxonomy of Holcoglossum s.l. by using light and scanning electron microscopy to analyze 38 samples representing 12 species of Holcoglossum, with five species from five closely related genera, such as Ascocentrum, Luisia, Papilionanthe, Rhynchostylis and Vanda. Our results indicated that Holcoglossum can be distinguished from the related genera based on cuticular wax characteristics, and the inclusion of Holcoglossum himalaicum in Holcoglossum is supported by the epidermis characteristics found by LM and SEM. The percentage of the tetracytic, brachyparacytic, and laterocytic stomata types as well as the stomata index and certain combinations of special wax types support infrageneric clades and phylogenetic relationships that have been inferred from molecular data. Laterocytic and polarcytic stomata are perhaps ecological adaptations to the strong winds and ample rains in the alpine region of the Hengduanshan Mountains.     

Pollination system of Holcoglossum rupestre (Orchidaceae): A special and unstable system

The pollination system of Holcoglossum rupestre was studied in northwestern Yunnan. The species is self-compatible but pollinator-dependent and offers nectar as a reward to visitors. A species of beetle, Hybovalgus bioculatus Kolbe, is identified as the pollinator among all visitors observed. The beetles carried the pollinia in two different positions, i.e. on the buttock and the foreleg, and pollinated the flowers by two different mechanisms. The analysis suggests that Holcoglossum rupestre and its pollinator may be in an unstable pollination relationship. The natural fruit set is low, which is attributed to the low visiting frequency of pollinator and the effective mechanism to prevent self-pollination.     

The genus Chamaegastrodia (Orchidaceae)

A merger of the genera Evrardia and Chamaegastrodia is proposed, and an annotated enumeration of five species so far recognized is proposed.     

Notes on the genus Pteroceras (Orchidaceae)

A new name (Pteroceras semiteretifolium H. Æ. Peders.) and two new combinations (P. cladostachyum (Hook.f.) H. Æ. Peders., P. unguiculatum (Lindley) H. Æ. Peders.) are presented. The correct application of the name P. pallidum (Blume) Holttum is discussed.     

Thysanoptera of the genus Dichromothrips on Old World Orchidaceae

Species of Dichromothrips are shown to be widespread on Orchidaceae in the Old World Tropics from Africa to New Zealand. The centre of diversity appears to be the Malaysian Region but this may be an artefact resulting from poor collections. The genus is redefined, its relationships discussed and a key provided to the 14 species [ australiae sp. nov., borneensis (Pr.); corbetti (Pr.); dendrobii Saki.; indicus sp. nov.; maori sp. nov._; nakahari sp. nov._; nigeriae sp. nov.; orchidis Pr.; phalaenopsidis Saki. (= sakimurai Bhatti syn.nov.); priesneri (Hood); semicognitus Saki.; smithi (Zimm.)j via torus sp. nov.|. Eugeneothrips Hood is synonymised with Dichromothrips.     

兰科虎舌兰属Epipogium种类增补与修订

报道日本虎舌兰Epipogium japonicum Makino在中国四川西部的新记录,并讨论了该种与虎舌兰E. roseum (D. Don) Lindl.的形态差异。过去将日本虎舌兰处理为虎舌兰的异名是不恰当的。日本虎舌兰间断分布于日本和中国的四川西部高海拔地区及台湾。     

Holcoglossum nujiangense (Orchidaceae: Aeridinae) – a new species and its pollination system

Based on herbarium and field observations, a new species, Holcoglossum nujiangense , is described and illustrated. It is morphologically similar to Holcoglossum sinicum and H. weixiense . Holcoglossum nujiangense differs from H. weixiense by smaller flowers with broadly rhombic midlobe and from H. sinicum by its broadly rhombic midlobe, papillose spur and notable callus on the disc. The chromosome number of this species was found to be 2n=38. The pollinator for this new species was Micraphis andreniformis Smith that carried the pollinia of Holcoglossum nujiangense on its head. The visiting behavior of the pollinator is food-search kind, although there is no obvious nectar in the spur.     

Nujiangia (Orchidaceae: Orchideae): A new genus from the Himalayas

The phylogenetic positions of the enigmatic “wildcard” taxon,Habenaria griffithii,were inferred from molecular data and morphological evidence.Morphologically,H.griffithii is quite “isolated” in Habena...     

Biosystematics of the genus Piperia Rydb. (Orchidaceae)

Piperia is a North American segregate of Habenaria consisting of 5 taxa (4 species and 1 subspecies). The genus is defined and differentiated from other North American genera of the Habenaria alliance by its morphology and pollination mechanism. All taxa have n = 21 chromosomes. Thin-layer chromatography of fresh leaf extracts and a morphological assessment revealed discrete, but variable, taxa. All species are partially interfertile; however, a high degree of sympatry suggests these species are reproductively isolated. One new combination is proposed: P. elongata subsp. michaelii.     

The systematic status of the genus bletilla (Orchidaceae)

The genusBletilla has been variously placed in the major classifications of the Orchidaceae. This study attempts to provide a better understanding of the relationships of this genus and to clarify its systematic position. A survey is provided of the taxonomic assignments ofBletilla in major classifications of the Orchidaceae, and morphological comparisons are made of species chosen to represent the generaBletilla, Arethusa, andBletia. Chromosome numbers reported forBletilla andBletia are summarized, and confirmatory counts of 2n =32 are reported forBletilla striata andB. striata f.gebina. A preliminary report is provided on intergeneric crossing studies. It was found thatBletilla consistently shows greater similarity toBletia than toArethusa. It is suggested, therefore, thatBletilla be removed from the subtribe Arethusinae and placed nearBletia in the Bletiinae.     

Studies in the genus Nervilia (Orchidaceae) in Africa

Taxonomy and nomenclature of six Nervilia species occurring in the Flora Zambesiaca area are revised. Lectotypes or neotypes are selected for all relevant taxa from Africa. The new species N. gassneri is described and the new combination N. kotschyi var. purpurata is made. One widespread African species previously mostly known under the names N. humilis and N. reniformis is shown to be conspecific with the widespread Asian and Australien species N. crociformis.     

New species of the genus Epistephium (Orchidaceae, Vanilloideae)

The morphological study of the herbarium material representing Epistephium (Orchidaceae, Vanilloideae) led to the discovery of two groups of specimens that significantly differ from all known species of the genus. The results of literature data study and of comparative analysis of those and other specimens suggest that these collections represent new taxa that we describe as E. garayi and E. kubiyuense. The distinguishing features of the species are indicated. As both new species are reported from Colombia (E. garayi, also from Guyana), the key for the determination of all Colombian representatives of the genus is included. Information on the ecology and distribution of newly described taxa is presented.     

Taxonomy of the genus Aspasia Lindley (Orchidaceae: Oncidieae)

The genusAspasia (Orchidaceae: Oncidieae) consists of five species of epiphytic orchids of Central and South America. The genus is compared with closely related genera of the tribe Oncidieae.Aspasia epidendroides is found in Nicaragua, Costa Rica, and western Panama.Aspasia principissa is found in central and eastern Panama and adjacent Colombia.Aspasia psittacina is endemic to western Ecuador.Aspasia variegata is found in Colombia, Venezuela, Trinidad, Guyana, Surinam, and Brazil.Aspasia lunata is known only from Brazil.     

A study of the genus leuconostoc

Summary Leuconostocs from herbage and grass silage were compared with strains from culture collections. The organisms were divided into sections, on ability to form detectable amounts of H₂O₂ from glucose and dextran from sucrose, and into groups by various tests of which the most useful were catalase activity, ability to grow at various temperatures, manner of growth in glucose soft agar and action on pentoses. The satisfactory division of all these organisms into species on ability to ferment pentoses and sucrose and to form dextran from sucrose, the basis of Hucker and Pederson's (1931) classification, was not possible. No useful alternative scheme was apparent. The preference of one group of organisms for aerobic conditions coupled with their ability to form catalase when provided with haem compounds, suggests that leuconostocs may have evolved from organisms possessing a respiratory pathway.     

The genus Cremastra (Orchidaceae), a taxonomic revision

The genus Cremastra is revised. A total of 8 taxa have earlier been proposed, but in the present revision 2 species are recognized: C. appendiculata and C. unguiculata. Hyacinthorchis variabilis is here considered a variety: C. appendiculata var. variabilis comb. et stat. nov.