Macrosolen bidoupensis Tagane & V.S.Dang, sp. nov. (Loranthaceae) is newly described from Bidoup Nui Ba National Park in Lam Dong Province, southern Vietnam. The new species is characterized by small broadly elliptic to circular leaves, sessile to short petioles, slightly cordate to rounded leaf bases, 4–5 pairs of lateral veins and a basally green corolla tube. An illustration, a summary of DNA barcoding of the plastid genes rbcL and matK, and a key to the species of Macrosolen in Vietnam are provided.

Phyllagathis phamhoangii, a species from Vietnam, was originally described in Phyllagathis based on its resemblance to P. nanakorniana and P. subrotunda in habit, rhizome morphology and leaf shape. However, its overall morphology, mainly stamen and capsule morphology, corresponds better with Fordiophyton indicating questionable generic affiliation. We included molecular (nrITS) and anatomical (crystal form) evidences to resolve the generic affiliation of P. phamhoangii. Our phylogenetic analyses recovered P. phamhoangii inside Fordiophyton and P. nanakorniana and P. subrotunda inside the Kerriothyrsus clade. The Fordiophyton clade is characterized by the presence of raphides, while the Kerriothyrsus clade is characterized by druses. Based on these evidences, P. phamhoangii is herein transferred to Fordiophyton, resulting in a new combination F. phamhoangii. It is morphologically similar to F. peperomiifolium but differs from the latter in the leaf blade with shortly acuminate to acuminate apex (vs. broadly acute), hypanthium 4-ridged (vs. not ridged), and connectives of shorter stamens dorsally spurred (vs. not spurred).

Thismia claviformis Chantanaorr. & J. Wai, is described and illustrated as a new species from the Thai-Malay Peninsula. The new species is characterized by 1) vermiform underground parts, 2) equal perianth lobes with slender claviform appendages, 3) a perianth tube without transverse bars inside, and 4) the apex of stamen bearing two triangular lobes. A taxonomic description, illustrations of the new species and a comparison with the related species are presented.

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Abstract. Goodyera lanceolata Ridl., a rare orchid species previously known only from Selangor, Peninsular Malaysia, was newly discovered in lower montane forests in southern Thailand. A description, line drawings and photographs are provided, and its diagnostic characters and geographical distribution are briefly discussed.