General flowering (GF), irregular synchronous mass flowering of multiple tree species across multiple families, is a unique biological phenomenon of the mixed lowland dipterocarp forest in Southeast Asia. Characterizing the spatial extent and temporal dynamics of GF is essential for an improved understanding of climate–vegetation interactions and the potential climate change impact on this species‐rich rainforest. We investigated the utility of newly available high‐temporal (daily) and high‐spatial (3–4 m) resolution remote sensing by the PlanetScope commercial satellite constellation for detecting flowering trees in a dipterocarp rainforest at Lambir Hills National Park, Sarawak, Malaysia. Our study was focused on the latest GF event known to have occurred in the region in the year 2019. PlanetScope successfully acquired 13 clear‐sky or minimally cloud‐contaminated scenes over the park during a study period of January 1, 2019 to August 31, 2019 encompassing the 2019 GF event. In situ phenology observations verified that the PlanetScope images detected the flowering crowns of tree species that turned into white or orange. This multitemporal image dataset also captured the flowering peak and species differences. The correlation coefficients between the multitemporal image signatures and in situ phenology observations were moderate to very strong (0.52–0.85). The results indicated that the 2019 GF event was a whole‐park phenomenon with the flowering peak in May. This study reports the first successful satellite‐based observations of a GF event and suggests the possibility of regional‐scale characterization of species‐level phenology in the dipterocarp forest, key information for biodiversity conservation in Southeast Asia.

The phylogeny of the Colocasiomyia cristata species group is reconstructed as a hypothesis, based on DNA sequences of two mitochondrial and six nuclear genes and 51 morphological characters. The resulting tree splits this species group into two clades, one of which corresponds to the colocasiae subgroup. Therefore, a new species subgroup named as the cristata subgroup is established for the other clade. Within the cristata subgroup, three subclades are recognized and each of them is defined as a species complex: the cristata complex composed of five species (including three new ones: C. kinabaluana sp. nov., C. kotana sp. nov. and C. matthewsi sp. nov.), the sabahana complex of two species (C. sabahana sp. nov. and C. sarawakana sp. nov.), and the xenalocasiae complex of five species (including C. sumatrana sp. nov. and C. leucocasiae sp. nov.). There are, however, three new species (C. ecornuta sp. nov., C. grandis sp. nov. and C. vieti sp. nov.) not assigned to any species complex. In addition, breeding habits are described for four cristata-subgroup species, each of which monopolizes its specific host plant. And, data of host-plant use are compiled for all species of the cristata group from records at various localities in the Oriental and Papuan regions. The evolution of host-plant selection and sharing modes is considered by mapping host-plant genera of each species on the phylogenetic tree resulting from the present study.

Bulbophyllum abangjoei is a new one-flowered orchid species described from Lanjak Entimau Wildlife Sanctuary, Katibas and Anap-Muput, Tatau, Sarawak. The taxonomic treatment is accompanied by taxonomic notes, information on the species’ affinities at infrageneric level, geographical distribution, habitat ecology, and implications for their conservation. It is morphologically almost similar to Bulbophyllum deviantiae, B. membranifolium, and B. sanguineolentum, but clearly differs in the long, narrowly oblong to linear leaf blade, subsessile petiole ca. 5 mm long, long narrowly cylindrical pseudobulbs with some mature pseudobulbs reaching ¾ length of the leaf blade, non-resupinate flowers, shortly upcurved and not emarginate labellum apex, and elliptic-oblong stelids at lower margins near the apex of the column. For these morphological differences, B. abangjoei is here described as distinct and new species to science. The new species is so far only known from three localities in protected areas in Sarawak, and hereby is assessed as ‘Endangered’ [EN B2 (a)(b) D1] under IUCN Red List criteria B and D.

We report new findings on two orchids from protected forests in Pahang, Peninsular Malaysia: the mycoheterotrophic Aphyllorchis striata and the epiphytic Acriopsis densiflora var. subpandurata, a newly described variety. Recently collected material enables a reassessment of their morphology and resolution of outstanding taxonomic ambiguities. For A. striata, we provide an updated species description, an identification key for Aphyllorchis in Peninsular Malaysia and Thailand, and designate an epitype to address limitations in earlier type material. For A. densiflora var. subpandurata, we describe the new variety based on its distinct few-flowered inflorescence (8-flowered) and subpandurate labellum and designate its holotype.