Twelve Pteridophytes of six families are reported from Bolaven Plateau, southern Laos, as new records to the flora of Laos. For each species, voucher specimens, photographs, and additional information including geographical distribution, ecology and taxonomic notes are provided.

Land application of treated palm oil mill effluent (TPOME) could be used as an alternative tertiary wastewater treatment process. However, phenolic compounds in TPOME might be leached to the environment. This study investigated the ability of grasses on reducing phenolic compounds in the leachate after TPOME application. Several pasture grasses in soil pots were compared after irrigating with TPOME from stabilization ponds, which contained 360-630 mg/L phenolic compounds. The number of soil bacteria in planted pots increased over time with the average of 10 8 CFU/g for mature grasses, while only 10 4-10 6 CFU/g were found in the unplanted control pots. The leachates from TPOME irrigated grass pots contained lower amounts of phenolic compounds and had lower phytotoxicity than that of control pots. The phenol removal efficiency of grass pots was ranged 67-93% and depended on grass cultivars, initial concentration of phenolic compounds and frequency of irrigations. When compared to water irrigation, TPOME led to an increased phenolic compounds accumulation in grass tissues and decreased biomass of Brachiaria hybrid and Brachiaria humidicola but not Panicum maximum. Consequently, the application of TPOME could be conducted on grassland and the grass species should be selected based on the utilization of grass biomass afterward.

Dendrobium fuscifaucium is described here as a new species from Laos PDR. This species was found at a local nursery and was claimed to have been collected from the limestone mountains of Kasi District (Vientiane Province). Detailed description and comparison, comparison with its allied species, D. hekouense, D. luoi and D. wangliangii is provided, along with flowering phenology and information on habitat. Multiple attempts have failed to locate this species in the wild.

A new species of Paraboea (Gesneriaceae), P. khotamiae, from a limestone karst in central Laos, is described and illustrated. The species resembles Paraboea bintangensis, P. prazeri and P. robusta, but differs in leaf shape and floral features, especially corolla shape and size, the interior of the corolla tube, and capsule characters. In addition, we report the occurrence of Middletonia reticulata (Gesneriaceae) for the flora of Laos for the first time.

Six new species of Gesneriaceae from Laos, namely Didymocarpus angustiflorus Souvann. & Lanors., D. bolavenensis Souvann., Soulad. & Phonep., D. laoticus Souvann. & Lanors., D. trilobus Souvann. & Phonep., Hemiboea olivifolia Souvann. & Tagane and Paraboea planiflora Souvann. & Lanors., are described and illustrated. Additionally, Aeschynanthus bracteatus Wall. ex A.DC., A. micranthus C.B.Clarke, Epithema ceylanicum Gardner, Lysionotus serratus D.Don, Microchirita luteola C.Puglisi, Paraboea swinhoei (Hance) B.L.Burtt, Petrocosmea kerrii Craib and Pseudochirita guangxiensis (S.Z.Huang) W.T.Wang, are newly recorded for the flora of Laos.