Corybas

Abstract:  Premise of the study: In addition to autotrophic and fully mycoheterotrophic representatives, the orchid family comprises species that at maturity obtain C and N partially from fungal sources. These partial mycoheterotrophs are often associated with fungi that simultaneously form ectomycorrhizas with trees. This study investigates mycorrhizal nutrition for orchids from the southwestern Australian biodiversity hotspot.  Methods: The mycorrhizal fungi of 35 green and one achlorophyllous orchid species were analyzed using molecular methods. Nutritional mode was identifi ed for 27 species by C and N isotope abundance analysis in comparison to non-orchids from the same habitat. As a complementary approach, 13 CO 2 pulse labeling was applied to a subset of six orchid species to measure photosynthetic capacity.  Key results: Almost all orchids associated with rhizoctonia-forming fungi. Due to much higher than expected variation within the co-occurring nonorchid reference plants, the stable isotope approach proved challenging for assigning most orchids to a specialized nutritional mode; therefore, these orchids were classifi ed as autotrophic at maturity. The 13 CO 2 pulse labeling confi rmed full autotrophy for six selected species. Nonetheless, at least three orchid species ( Gastrodia lacista , Prasophyllum elatum , Corybas recurvus ) were identifi ed as nutritionally distinctive from autotrophic orchids and reference plants.  Conclusions: Despite the orchid-rich fl ora in southwestern Australia, partial mycoheterotrophy among these orchids is less common than in other parts of the world, most likely because most associate with saprotrophic fungi rather than ectomycorrhizal fungi.

Abstract: In this report, two newly discovered native orchids, Corybas shanlinshiensis and Nervilia crociformis, are presented. Also description and figures of Dendrobium luzonense were provided.

Abstract: Corybas is an elusive terrestrial orchid genus mostly inhabiting the high peaks in Peninsular Malaysia, which is the most vulnerable habitat to climate change. Nine species, of which seven are endemic, were studied based on natural populations, whereas information on another two was obtained from herbarium collections. Corybas caudatus was excluded from the study due to insufficient materials, and the type was not located. The species investigated were growing in small populations in the remaining moss-covered forests in the highlands. Human activities and temperature rise are two major threats to the wild populations. Our field observations revealed that Corybas species are good indicators of climate change as they are highly sensitive to temperature rise and drop in relative humidity. Judging from the current small number of specimens recollected, the small population sizes and degraded habitats where they grow, Corybas species in Peninsular Malaysia are all threatened by extinction in the wild.

Abstract: . Hartini S. 2019. Orchids Diversity in the Sicikeh-Cikeh Forest, North Sumatra, Indonesia. Biodiversitas 20: 1087-1096. Sicikeh-cikeh forest includes three forest areas, namely Adian Tinjoan Customary Forest, Adian Tinjoan Protection Forest, and Taman Wisata Alam Sicikeh-cikeh. Typical vegetation of this area is mountain forest with large diversity of plant species. Among the species, orchid is one of the potential plants found diversely in this location and has not yet been recorded. The exploration activities were conducted at Sicikeh-cikeh forest. Orchid exploration was conducted to collect living plants for ex situ conservation purpose. Orchid inventory, to record orchid diversity in this area, was based on plant collection by purposive random sampling. The results of the study recorded approximately 102 different species from 30 genera of orchids in this area. Typical epiphytic and terrestrial highland orchids were found and very common in Sumatra. Among the species found are endemic Sumatra, such as Coelogyne brachygyne, Coelogyne salmonicolor, Dendrobium kruiense, Epigeneium pulchellum, Thrixspermum gombakense, Corybas stenotribonos and Paphiopedilum tonsum. Interesting terrestrial orchids include Kuhlhasseltia javanica, Neuwiedia zollingeri var. javanica, Paphiopedilum tonsum, Phaius callosus, Corybas stenotribonos, Calanthe aurantiaca, Calanthe chrysoglossoides, and Calanthe pulchra. While interesting epiphytic orchids include Bulbophyllum absconditum, Bulbophyllum coloriferum, Coelogyne brachygyne, Epigenium pulchellum, Eria bractescens, Eria pachystachya, Pholidota gibbosa, and Thrixspermum amplexicaule.