Global exchange and accumulation of non-native plants.

All around the globe, humans have greatly altered the abiotic and biotic environment with ever-increasing speed. One defining feature of the Anthropocene epoch is the erosion of biogeographical barriers by human-mediated dispersal of species into new regions, where they can naturalize and cause ecological, economic and social damage. So far, no comprehensive analysis of the global accumulation and exchange of alien plant species between continents has been performed, primarily because of a lack of data. Here we bridge this knowledge gap by using a unique global database on the occurrences of naturalized alien plant species in 481 mainland and 362 island regions. In total, 13,168 plant species, corresponding to 3.9% of the extant global vascular flora, or approximately the size of the native European flora, have become naturalized somewhere on the globe as a result of human activity. North America has accumulated the largest number of naturalized species, whereas the Pacific Islands show the fastest increase in species numbers with respect to their land area. Continents in the Northern Hemisphere have been the major donors of naturalized alien species to all other continents. Our results quantify for the first time the extent of plant naturalizations worldwide, and illustrate the urgent need for globally integrated efforts to control, manage and understand the spread of alien species.

Lasianthus ranongensis (Rubiaceae), a new species from Andaman tropical rainforest Thailand.

We describe Lasianthus ranongensis Sinbumr. & Napiroon as a new species in the genus Lasianthus. The new taxon is intensively discussed through taxonomic affinities and information on its habitat, distribution and conservation status is provided. Moreover, line drawings and stereo microscope images of important fertile organs are demonstrated. The new species is morphologically similar to L. stipularis but differs in its having flattened branches (vs. terete), leaf blade elliptic-oblong shape of 15.0-20.0 × 4.0-6.0 cm (vs. oblanceolate-oblong 12.0-16.0 × 3.0-5.5 cm), 9-12 pairs of veins (vs. 9-10 pairs), stipule 5-7 mm long, half covering cymes (vs. 10-12.5 mm long, entirely covering cymes), four or five bracts narrowly lanceolate, 2.5-3.0 mm long (vs. bracts numerous, broadly triangular, 10-15 mm), flowers with cupular calyx (vs. with campanulate calyx), corolla villous on internal surface, and six or seven lobed (vs. pubescent on internal surface and four lobed) and drupes with five pyrenes (vs. with four pyrenes). It is also similar to L. pseudo-stipularis, but from which it is obviously distinguished by its stipule half covers cymes, secondary veins have 9-12 pairs of secondary veins, cupular calyx shape, six or seven lobed corolla, and drupe with five pyrenes, whereas L. pseudo-stipularis has stipule entirely covering cymes, 7-8 pairs of secondary veins, obconic calyx, four lobed corolla, and drupe with four pyrenes.

Causonissessilifolia (Vitaceae), a new species from Thailand.

A new species, Causonissessilifolia, from Thailand is described, based on morphological and phylogenetical methods. A full description, conservation assessment, a key, images and phylogenetic tree are provided. Diagnostic characters for this species are sessile leaves that are sometimes opposite and inflorescence insertion interfoliar.

Corybaspapillatus (Orchidaceae), a new orchid species from peninsular Thailand.

A new species, Corybaspapillatus, is described and illustrated from peninsular Thailand. The new species is easily recognized through a combination of the following characters: the purplish flower, the rounded apex of the dorsal sepal, the outer surface of dorsal sepal covered with irregular papillae in the upper half, the lateral sepals adnate laterally at the base to the connate petals, the V-shaped throat, the labellum bearing short hairs, dentate to erose labellum margins, and well-developed conical spurs. A key to the species of Corybas in Thailand is presented.

Cannabinoids from inflorescences fractions of Trema orientalis (L.) Blume (Cannabaceae) against human pathogenic bacteria.

BACKGROUND: Cannabinoids; tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN), might show antibacterial activity. Trema orientalis is a species in the Cannabaceae that is closely related to Cannabis through plastome phylogenetic evidence. This species is widely distributed throughout tropical Asia and is used as traditional medicine, particularly for the treatment of infectious diseases. However, no studies on the antibacterial activity of cannabinoid-containing inflorescences extracts are available. Thus, the aim of this study was to determine cannabinoid content and antibacterial activity of inflorescences fractions from T. orientalis native to Thailand. METHODS: We hypothesized that inflorescences from T. orientalis might display cannabinoids similar to Cannabis because of their close taxonomic relationship. We extracted the mature inflorescences and infructescence of T. orientalis in three disparate populations from different Thailand floristic regions. Extractions were subsequently partitioned into hydrophilic and lipophilic fractions using distilled water and chloroform. The lipophilic extracts were further fractionated by the column chromatography with gradient elution and analyzed by gas chromatography-mass spectrometry (GC-MS). Characterized cannabinoids were used in bioassays with multidrug-resistance bacteria. RESULTS: Lipophilic extracts and fractions of inflorescences from all Thailand floristic regions consistently displayed cannabinoids (THC, CBD and CBN) in various quantities. These extracts exhibited inhibitory activity for Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii strains with minimum inhibitory concentration values varying from 31.25 to 125 µg/mL. CONCLUSION: Our study is the first to report cannabinoid detection in extracts from inflorescences of T. orientalis, a species in the Cannabaceae. These extracts and their fractions containing cannabinoids showed pronounced antibacterial activity. The use of analytic methods also demonstrated reproducible cannabinoid extraction.