Abstract. Batuyong MAR, Calaramo MA, Alejandro GJD. 2020. A checklist and conservation status of vascular plants in the Limestone forest of Metropolitan Ilocos Norte Watershed Forest Reserve, Northwestern Luzon, Philippines. Biodiversitas 21: 3969-3981. The Metropolitan Ilocos Norte Watershed Forest Reserve (MINWFR) is among the remaining intact limestone formations and a critical protected area in Northwestern Luzon. There have been few published floristic studies despite its undeniable rich biological importance. Therefore, this paper primarily aims to provide a preliminary checklist of vascular plants in MINWFR and their conservation status.  Consequent field visits and surveys were made from April 2019 to March 2020. Results revealed a total of 173 species distributed in 140 genera belonging to 59 families. The most represented families are Rubiaceae, Fabaceae, Orchidaceae, and  Malvaceae. This forest supports 49% or 28.65 % local endemics, five of which are narrow endemics, namely Cyanometra warburgii, Pyrostria triflora, Syzygium ilocanum, Thrixspermum nicolasiorum, and Antirhea microphylla. The latter, however, extends up to Ilocos Sur. Based on IUCN criteria and DENR records, a total of 18 species are threatened, one species is recorded as critically endangered, five endangered, nine vulnerable, three other threatened, two near threatened, 55 as least concern, and the rest are not evaluated. Other noteworthy species present in the area are the two dominant endangered species, Podocarpus costalis, and Podocarpus polystachyus. An interesting spinescent Rubiaceae species were recorded and currently under examination to establish its identity. This checklist serves as a basis to effectively manage this vulnerable area surrounded by human-induced disturbances and threats.

Abstract. Batuyong MAR, Calaramo MA, Alejandro GJD. 2021. Inventory of Rubiaceae species in Mt. Pao Range, Ilocos Norte, Northwestern Luzon, Philippines. Biodiversitas 22: 3604-3612. Botanical assessments in the Philippines are mostly conducted on declared Protected Areas (PAs). However, many remaining potentially interesting and largely unexplored floristic sites are not considered PA, one of which is the Mt. Pao Range in the Municipality of Adams, located in Ilocos Norte, Philippines. Among the flowering plant family, Rubiaceae is one with the largest number of endemic species and genera in the Philippines Thus, floristic surveys of Rubiaceae species were conducted, and collections were made from September 2019 to March 2021. A total of 39 species belonging to 13 tribes and 24 genera of the family were recorded. These constitute 7.09% of the total Philippine Rubiaceae. Of these species, 18 are Philippine endemics while two are considered narrow endemic to Mt. Pao. Two endemic genera were also found in the area  Antherostele and Kanapia. According to the Updated National List of Threatened Philippine Plants, their conservation status in the Department of Environment and Natural Resources (DENR) Administrative Order No. 2017-11 found one species assessed as Critically Endangered (Antherostele callophylla). This study contributes to the data on the distribution and occurrence of Philippine Rubiaceae. Moreover, it also highlights the area's importance with the presence of threatened and endemic species as an area of concern for protection and conservation.

Recent exploration on the northern Cordillera Mountain Range of Ilocos Norte, Philippines, resulted in the rediscovery of Psychotria palimlimensis Sohmer & A.P. Davis. This is an endemic Psychotria species first collected by Ramos in 1918 and identified as P. subalpina. However, the diagnosis of Sohmer and A.P. Davis in 2007 proposed it as a new species based on herbarium materials, and no further recollection was made to date since its last collection in 1953. Therefore, an amended taxonomic description of P. palimlimensis is proposed with color photographs, additional records on the distribution and morphological comparison with its allied species. The current conservation status is also provided.

The northern Cordillera Mountain Range of Ilocos Norte is an important site for floristic studies in the northwestern part of the Philippines. However, most of its forested areas remain understudied and limited data are available on the structure of its floristic communities. Here, a preliminary checklist of Rubiaceae species in Ilocos Norte is provided with notes on their distribution and conservation status. The field survey was conducted from April 2019 to March 2020 in Kalbario Patapat Natural Park (KPNP), Metropolitan Ilocos Norte Watershed Forest Reserve (MINWFR), and Mt. Lammin. A total of 57 species belonging to 28 genera and 15 tribes were recorded, which constitute 10.36% of the total number of Philippine Rubiaceae species. The genera with the highest number of recorded species are Psychotria, Ixora, and Ophiorrhiza with nine, six, and four species, respectively. Of these species, 27 are Philippine endemics that are widely distributed, and four species are endemic to the province. Among the sites surveyed, the tropical evergreen lowland rain forest of KPNP had the highest number of recorded species. With regard to their conservation status according to the IUCN (International Union for Conservation of Nature) red list category, one was assessed as Endangered. Moreover, based on the updated national list of threatened Philippine plants and their categories identified in the DENR (Department of Environment and Natural Resources) AO (Administrative Order) No. 2017-11, two are listed as Threatened species, one Critically Endangered, and one Vulnerable. According to the IUCN red list categories and criteria (2019), the four endemic species in the province recognized in the study are categorized as follows: one Critically Endangered (Antherostele callophylla), one Endangered (Psychotria tayabensis var. castanea), and two Vulnerable (Antirhea microphylla and Pyrostria triflora).