Significant collections of Orchidaceae conserved in Herbarium Hamburgense (HBG)

An inventory of critical type material in the recently rediscovered Kraenzlin Orchid Herbarium is presented. In addition, a partial inventory of type material of Orchidaceae conserved in the general herbarium at Hamburg (HBG) is presented as a guide to the collections.     

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.     

Orchid biogeography and factors associated with rarity in a biodiversity hotspot,the Southwest Australian Floristic Region

Aim The causes of orchid diversification and intrinsic rarity are poorly resolved. The Orchidaceae of the Southwest Australian Floristic Region use a diversity of pollination strategies and sites of mycorrhizal infection, and occupy a diversity of habitats. We combined a biogeographic analysis with analysis of factors associated with rarity to establish: (1) the landscape features correlated with taxon turnover and speciation, and (2) the possible role in taxon rarity of geographic region, pollination strategy, edaphic habitat and site of mycorrhizal infection. Location Southwest Australian Floristic Region. Methods The distributions of 407 orchid taxa (species and subspecies) were mapped at the quarter‐degree scale using 13,267 collections in the Western Australian Herbarium. This database was used to map taxon richness, for a biogeographic analysis and to quantify rarity of taxa. Using herbarium records, rarity was expressed as mean abundance, mean distribution and incidence of rarity based on abundance and distribution for each genus. We tested for differences in rarity of species between pollination strategies, edaphic habitats and sites of mycorrhizal infection. Results Taxon richness was highest in the High Rainfall Province. Biogeographic provincial boundaries for orchids were aligned with rainfall, while district boundaries tended to follow geological formations. When rarity was defined as either low abundance or small distribution, the greatest number of rare taxa occurred in areas of high taxon richness and naturally fragmented edaphic environments. For both abundance and distributional extent, sexual deception had a significantly higher incidence of rarity than food‐rewarding taxa. There was no significant difference in rarity with site of mycorrhizal infection. Main conclusions While large‐scale edaphic and climatic variation are correlated with orchid taxon turnover and speciation in a similar fashion to the flora in general, the processes responsible for patterns of diversity may differ. Fragmented edaphic environments appear to be associated with a higher incidence of rare species due to limited dispersal/colonization opportunities or radiations of taxa in allopatry. The high incidence of rarity in sexually deceptive taxa could be due to either low fruit set or the risk of specializing on a single pollinator species.     

Systematics of the Dactylorhiza euxina/incarnata/maculata polyploid complex (Orchidaceae) in Turkey: evidence from allozyme data

 Material of Dactylorhiza were sampled from 49 localities in Turkey and investigated for allozyme variation at ten loci (nine enzyme systems). Among diploids, the Anatolian D. osmanica and D. umbrosa were allozymically variable, but not distinct from each other or from D. incarnata. Dactylorhiza saccifera contained the same alleles as the European D. fuchsii. Dactylorhiza iberica and D. euxina were distinct from each other and the other diploids. On basis of allozyme patterns three distinct allotetraploid genotypes were distinguished, and each of them could be treated as a separate species. Dactylorhiza nieschalkiorum is similar to European allotetraploids, and may have arisen from hybridization between D. incarnata s.l. and D. saccifera. Dactylorhiza urvilleana may have arisen from parents related to present-day D. saccifera and D. euxina, but it also contains additional alleles that have not been found in any of the diploids investigated. A third allotetraploid known from four populations in the Ardahan and Kars provinces of north-eastern Turkey combines the allozyme patterns found in material of D. incarnata s.l. from the same area with those from D. euxina. It is here described for the first time as D. armeniaca. Received November 14, 2000 Accepted June 20, 2001     

Sheltered from the storm? Population viability analysis of a rare endemic under periodic catastrophe regimes

Rare species are important targets for biodiversity conservation efforts because rarity often equates to small populations and increased endangerment. Rare species are prone to stochastic extinction events and may be particularly susceptible to catastrophes. Therefore, understanding how rare species respond to disturbances is critical for evaluating extinction risk and guiding conservation managers. Population viability analyses (PVAs) are essential for assessing rare species' status yet they seldom consider catastrophic events. Accordingly, we present a PVA of a rare tropical epiphyte, Lepanthes caritensis (Orchidaceae), under simulated disturbance regimes to evaluate its demographics and extinction risk. We aimed to test how demographic models incorporating catastrophes affect population viability estimates. Our goal was to better guide management of these orchids and other rare plants. Results revealed L. caritensis numbers have declined recently, but projected growth rates indicated that most subpopulations should increase in size if undisturbed. Still, projection models show that moderate catastrophes reduce growth rates, increase stochasticity in subpopulation sizes, and elevate extinction risk. Severe catastrophes had a more pronounced effect in simulations; growth rates fell below replacement level, there was greater variation in projected population sizes, and extinction risk was significantly higher. PVAs incorporating periodic catastrophes indicate that rare species may have greater extinction probabilities than standard models suggest. Thus, precautionary conservation measures should be taken in disturbance prone settings and we encourage careful monitoring after environmental catastrophes. Future rare plant PVAs should incorporate catastrophes and aim to determine if rescue and reintroduction efforts are necessary after disturbances to insure long-term population viability.     

Comparative study of nutritional mode and mycorrhizal fungi in green and albino variants of Goodyera velutina,an orchid mainly utilizing saprotrophic rhizoctonia

The majority of chlorophyllous orchids form mycorrhizal associations with so‐called rhizoctonia fungi, a phylogenetically heterogeneous assemblage of predominantly saprotrophic fungi in Ceratobasidiaceae, Tulasnellaceae, and Serendipitaceae. It is still a matter of debate whether adult orchids mainly associated with rhizoctonia species are partially mycoheterotrophic. Here, we investigated the nutritional modes of green and albino variants of Goodyera velutina, an orchid species considered to be mainly associated with Ceratobasidium spp., by measuring their ¹³C and ¹⁵N abundances, and by molecular barcoding of their mycorrhizal fungi. Molecular analysis revealed that both green and albino variants of G. velutina harbored a similar range of mycobionts, mainly saprotrophic Ceratobasidium spp., Tulasnella spp., and ectomycorrhizal Russula spp. In addition, stable isotope analysis revealed that albino variants were significantly enriched in ¹³C but not so greatly in ¹⁵N, suggesting that saprotrophic Ceratobasidium spp. and Tulasnella spp. are their main carbon source. However, in green variants, ¹³C levels were depleted and those of ¹⁵N were indistinguishable from the co‐occurring autotrophic plants. Therefore, we concluded that the albino G. velutina variants are fully mycoheterotrophic plants whose C derives mainly from saprotrophic rhizoctonia, while the green G. velutina variants are mainly autotrophic plants, at least at our study site, in spite of their additional associations with ectomycorrhizal fungi. This is the first report demonstrating that adult nonphotosynthetic albino variants can obtain their nutrition mainly from nonectomycorrhizal rhizoctonia.     

美花石斛化学成分及其护肤活性研究

本文研究美花石斛(Dendrobium loddigesii)的化学成分及其护肤活性。采用色谱法从美花石斛粗提物中分离得到12个化合物,利用波谱学方法分别鉴定为拖鞋状石斛素(1)、2,4,7-三羟基-9,10-二氢菲(2)、3,6,9-三羟基-3,4-二氢蒽-1(2H)-酮(3)、3,5′-二甲氧基-3′,4,9′-三羟基-7′,9-环氧-8,8′-木酚素(4)、5-(4-羟基-3-甲氧基苯乙基)-2-(4-羟基-3-甲氧基苯基)苯并二氢呋喃-3,7-二醇(5)、5-(4′′-羟基-3′′-甲氧基苯乙基)-2-(4′-羟基-5′-甲氧基苯基)-7-甲氧基苯并二氢吡喃-3-醇(6)、丁香脂素(7)、异香草醛(8)、松柏醛(9)、2-甲氧基-5-羟甲基苯酚(10)、二氢松柏醇(11)、4-羟基-3-甲氧基苯乙醇(12)。其中化合物3～5、7～12为首次从美花石斛中分离得到;化合物1、2、6(100μg/mL)有一定的自由基清除活性(>80%);化合物2(10μg/mL)有一定促胶原蛋白分泌活性(>20%)。结果显示从美花石斛的茎中分离得到了12个化合物,3个表现出良好的护肤活性。     

中国兰科独蒜兰属植物增补

报道了中国兰科独蒜兰属2个未详知种:藏南独蒜兰(Pleione arunachalensis Hareesh, P.Kumar M.Sabu)和矮小独蒜兰[P.humilis (Sm.) D.Don],并提供了详细的形态描述和照片。凭证标本保存于云南省林业和草原科学院植物标本馆(YAF)。     

First report that the wasp Gronotoma guamensis (Hymenoptera: Figitidae: Eucoilinae) parasitizes the orchid‐feeding fly Japanagromyza tokunagai in Japan

Compared with mycorrhizal relationships, the relationships between mycoheterotrophic plants and insects have rarely been studied. Here we report a previously unknown tripartite interaction among an endangered mycoheterotrophic orchid, an orchid‐feeding fly, and a parasitoid wasp. The flowers and stems of Eulophia zollingeri were heavily attacked by Japanagromyza tokunagai (Sasakawa) (Diptera: Agromyzidae), and the parasitoid wasp Gronotoma guamensis (Yoshimoto) (Hymenoptera: Figitidae) was reared from these J. tokunagai individuals. Considering the high infestation rate of J. tokunagai, G. guamensis could be important in suppressing the J. tokunagai population, and positively affect the reproductive success of E. zollingeri.