Philippine Journal of Science 150 (S1): 487-502, Special Issue on Biodiversity ISSN 0031 - 7683 Date Received: 05 Oct 2020

Diversity of in Ilocos Norte, Northwestern Luzon, Philippines: A Preliminary Checklist, Their Distribution, and Conservation Status

Mae Ann R. Batuyong1,2, Michael A. Calaramo3, and Grecebio Jonathan D. Alejandro1,4

1The Graduate School, University of Santo Tomas España Blvd. 1015 Manila, Philippines 2Department of Biological Sciences, College of Arts and Sciences Mariano Marcos State University, City of Batac 2906 Ilocos Norte, Philippines 3Garden Director and Curator, Northwestern University Ecological Park & Botanical Garden Airport Ave., Bengcag, Laoag City 2900 Ilocos Norte, Philippines ,4College of Science and Research Center for the Natural & Applied Sciences University of Santo Tomas, España Blvd. 1015 Manila, Philippines

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 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 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 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).

Keywords: biodiversity, conservation, floristic survey, Ilocos Norte, tropical rain forest

*Corresponding Author: [email protected]

487 Philippine Journal of Science Batuyong et al.: Rubiaceae Species in Ilocos Vol. 150 No. S1, Special Issue on Biodiversity Norte, Northwestern Luzon, Philippines

INTRODUCTION Based on the comprehensive global assessment of the (Davis et al. 2009), the Philippines ranked among The Philippines is a top priority for biodiversity the 20 most diverse regions for Rubiaceae based on the conservation due to its rich flora and fauna and high total number of species and ranked third among the 20 endemism. This diversity is due to its tropical location, areas with the highest number of endemic species, wherein climatic conditions, and unique geological origins (Myers five genera are considered to be endemic to the country: et al. 2000; Brown et al. 2013). However, it is also one Antherostele Bremek., Greeniopsis Merr., Sulitia Merr., of the top countries considered as a biodiversity hotspot Villaria Rolfe, and the recently added Kanapia (Myers 1988, 1990, 2003; Myers et al. 2000; Mittermeier Arriola & Alejandro (Alejandro and Liede-Schumann et al. 2004, 2011; DENR-BMB 2015). The biota of many 2003; Alejandro 2007; Alejandro et al. 2010, 2011; of the regions in the country – which has a relative total Arriola et al. 2016). It is also one of the families land area of approximately 300,000 sq. km comprised of in the Philippines with the most number of threatened thousands of islands – is considered to be understudied, species (Fernando et al. 2008). Thus, the need for further and many of its flora and fauna are waiting to be described. taxonomic research on Rubiaceae is substantial. Although One important site for floristic studies in the northwestern the study of Ordas et al. (2019) provided a checklist of portion of the country is the northern Cordillera Mountain species of Rubiaceae in Eastern Samar Visayas, wherein Ranges in Ilocos Norte (Vallejo 2014). It is a part of the 37 out of the 59 species recorded are endemic. More northwestern mountains of Luzon Island – which covers studies of the plant family are necessary, such as studies the Kalinga-Apayao area in its northern part; the Ilocos- that will provide an update on the existing information, Cagayan boundary as its southern outpost; and Abra, especially on the occurrence and distribution of endemic including Ilocos Sur, as its western boundary. The area species. These are necessary for underpinning specific is composed of different types of terrestrial ecosystems species management plans for conservation and protection – from montane mossy forests and forests over limestone priorities (Harris 2012). to seasonally dry lowland tropical rain forests (Calaramo et al. 2016). It also contains the last frontier of contiguous old-growth forests in the Ilocos Region that extends to Cagayan and Cordillera (DENR 2018). Aside from these, MATERIALS AND METHODS several newly described plant species were documented from Ilocos Norte – such as Amorphophallus adamsensis Study Site (Magtoto et al. 2013), Begonia palemlemensis (Calaramo Fieldwork was conducted in four localities within the et al. 2019b), Dendrobium elineae (Naive et al. 2019), northern Cordillera Mountain Ranges of Ilocos Norte Nepenthes aenigma (Gronemeyer et al. 2016), Pyrostria covering the following – namely KPNP, MINWFR, and triflora (Arriola et al. 2015), Robiquetia ilocosnortensis Mt. Lammin. (Calaramo et al. 2019a), and Thrixpermum nicolasiorum (Calaramo et al. 2018). The KPNP (Figures 1, 2A, and 2B) is one of the remaining Natural Parks in the Philippines that retains Most of the forested areas in Ilocos Norte are still relatively its key biodiversity area status (DENR-BMB 2016). scarce on plant inventories. The works of Magtoto and It was established under Proclamation No. 1275 s. Austria (2017) on the pteridophytes of Adams and 2007, under Republic Act No. 7586 or the National Batuyong et al. (2020) on the checklist of vascular plants Integrated Protected Areas (NIPAS) Act of 1992. This in the limestone forest of MINWFR are the only recent 38-sq.-km natural park with a 19.37-sq.-km buffer floristic studies documented. According to Ong et al. zone is located on the mountains of the Municipalities (2002), the major challenge in conserving the country's of Pagudpud and Adams. KPNP is the only remaining biological diversity is that baseline information is limited, remnants of an old-growth mix dipterocarp forest on the incomplete, or lacking and widespread. Also, existing data northwestern portion of Luzon contiguous to Cagayan of previously recorded species need updating in terms of and Cordillera (DENR 2018). Its highest peak is part biology, distribution, occurrence, and abundance. Hence, of Mt. Palemlem range at 1,294 m above sea level to ensure this, there should be a maintained and continuing (masl). The KPNP is generally described as a tropical biological inventory. evergreen lowland rainforest and is bound by the 3 climate of Cagayan receiving a large amount of rainfall The Rubiaceae or coffee family represents one of throughout the monsoon season (Modified Corona the largest families of angiosperms of , , Climate Classification). geofructices, herbs, and (Robbrecht 1988) – with approximately 550 species in about 80 genera recognized The MINWFR (Figures 1 and 2D), on the other hand, in the country (Govaerts et al. 2006; Alejandro 2007). is considered one of the remaining important limestone

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Figure 1. Location of the study areas in Ilocos Norte, Northwestern Luzon, Philippines. Areas surveyed are marked in colors. areas found on the island of Luzon (Batuyong et al. It lies between geographical coordinates of 120°37'00"– 2020). Initially, it is established as a component by the 120°41'00" N and 18°21'00"–18°24'00" E and is described NIPAS through Presidential Proclamation No. 731 but is as a lowland forest. Like MINWFR, Mt Lammin also currently proposed to be a regular protected area (PA). has a Type I climate with two main seasons – dry from MINWFR is situated in the Municipality of Pasuquin with November–April when most trees lose their leaves and an estimated land area of 20.75 sq. km and a buffer zone wet the rest of the year. of 4.12 sq. km, lying between geographical coordinates of 120°37'00"–120°41'00" N and 18°21'00"–18°24'00" Processing of Permits E. The highest altitude in the municipality is 564 m Permits from respective local government units (LGU) directly adjacent to the PA. This PA is classified as Type were secured before the actual field survey and collection 1 climate (Modified Corona Climate Classification) with of specimens in these areas. A gratuitous permit (GP) was pronounced wet months from April–November, turning obtained from the DENR Region 1 Office with the GP the area into lush greenery where numerous seasonal No. 2019-007. herbs and shrubs grow and the trees sprawl into a thick canopy. Plants that can withstand the dry season remain only during the dry months, but the sparse and small Survey, Collection, Processing, and Identification of stunted trees over rocky ridges dominate such as the Specimens species Podocarpus polystachyus R. Br. ex Endl. and P. Subsequent field visits were conducted from March– costalis C. Presl. August of 2019 to map the sites and trails and for the initial documentation of the Rubiaceae species. Then, Mt. Lammin (Figures 1 and 2C) is situated in Piddig with the purposive collections and follow through survey and an elevation of 1,800 masl and an area of 64.74 sq. km.

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Figure 2. View of the selected study sites: A) Mt. Palemlem; B) from the top view of KPNP; C) view portion of Mt. Lammin during the dry season; D) limestone forest of MINWFR. Photos taken by M.A. Batuyong and M.A. Calaramo. final documentation were conducted from September org/cite.do; WCSP 2021). Besides, the Arc-GIS v. 10.5 2019–February 2020. The plant specimens were collected and Adobe Photoshop CC v. 20.0.8 were utilized for the along the entirety of the trail and 10 m within the trail. preparation of the maps and the figures. Then, duplicates or triplicates of each representative specimens were collected, pressed, dried, and mounted Determination of Endemicity and Conservation Status following standard procedures for herbarium vouchers. The occurrence and distribution of the Rubiaceae The specimens were identified initially in the field while species collected were based in Co's Digital Flora of unidentified specimens were brought to the herbarium for the Philippines (Pelser et al. 2011 onward) and Global further identification. Also, field photo documentation Biodiversity Information Facility (http://www.gbif.org/; was utilized and referred to online databases such as Co's GBIF 1999 onward). Digital Flora of the Philippines (https://www.phytoimages. siu.edu; Pelser et al. 2011 onward), JSTOR Plants (plants. The classification of the conservation status was adopted jstor.org; 2000 onward), and the Plants of the World Online using the red list of threatened species by the IUCN (2016) (http://www.plantsoftheworldonline.org). The collections and the updated national list of threatened plants in the from the following local herbaria – such as the Philippine Philippines (DENR AO 2017-11) in determining the National Herbarium (PNH), University of Santo Tomas status as Critically Endangered (CR), Endangered (EN), Herbarium (USTH), and Herbarium of Northwestern Vulnerable (VU), Other Threatened Species (OTS), Near Luzon (HNUL) – were also examined and compared to Threatened (NT), Least Concern (LC), Data Deficient the collected specimens to facilitate the identification. (DD), or Not Evaluated (NE). The living collections at the Northwestern University Ecological and Botanical Garden (NUEBG) were used as Local conservation assessment for the endemic species in cross-references for the collections, whereas the voucher the province was also determined following the conditions specimens were deposited at HNUL. The accepted presented in the guidelines for using the IUCN red list botanical names were referred to the World Checklist categories and criteria v. 14 (2019). of Selected Plant Families (https://wcsp.science.kew.

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RESULTS AND DISCUSSION (six species), Spermacoceae (five species), (four species), Ophiorrhizeae (four species), Lasiantheae (three species), Mussaendeae (three species), and List and Comparison of Recorded Species in the Urophyleae (three species). For the tribes Agusteae and Three Sites Argostemmateae, Gardenieae were represented by two In the Ilocos Norte Province, 57 Rubiaceae species were species each while the tribes Morindeae and Paederieae accounted belonging to 28 genera and 15 tribes (Table 1). were represented with one species each. These constitute 10.36% of the total Philippine Rubiaceae. Of these 57 recorded species, 22 species are shrubs, 20 As to the number of species collected among the surveyed small- to medium-sized trees, 10 herbs, and five lianas sites, KPNP had the highest number of species with (Figure 3A). The tribe having the highest number of 47, followed by MINWFR with a record of 19 and Mt. species was Psychotrieae (nine species) – followed by Lammin with only 16 species (Figure 3B). Ixoreae (six species), (six species) Vanguereae

Table 1. Preliminary list and distribution of Rubiaceae species in Ilocos Norte, Northwestern Luzon, Philippines. Habit (T – trees; H – herb; S – ; L – ), distribution, endemicity (E – endemic; NE – non-endemic), proposed status based on the IUCN red list of threatened species or the DENR AO 2017-11* (NE – Not Evaluated; DD – Data Deficient; VU – Vulnerable; EN – Endangered; CR – Critically Endangered), and accession numbers. Distribution Proposed Accession Species Habit Mt. Endemicity KPNP MINWFR status number Lammin Tribe Agusteae Wendlandia luzoniensis DC. T X X NE NE 0018523 Wendlandia philippinensis Cowan T X E EN 0018547 Tribe Argostemmateae Argostemma solaniflorum Elmer H X X NE NE 0018524 Mycetia javanica (Blume) Reinw. ex Korth. T X NE NE 0018548 Tribe Gardenieae Gardenia elata Ridl. T X NE NE 0018550 Tarennoidea wallichii (Hook.f.) Tirveng. & Sastre T X X X NE NE 0018534 Tribe Guettardeae Antirhea aff.benguetensis S X E NE 0018543 Antirhea microphylla (Bartl. ex DC.) Merr S X E NE 0018525 Guettarda speciosa L. T X NE LC 0018549 Timonius ternifolius (Bartl. ex DC.) Fern. -Vill. T X X E NE 0018526 Tribe Ixoreaea Ixora cf. auriculata S X E NE 0018551 Ixora bibracteata Elmer S X E NE 0018552 Ixora cumingiana S.Vidal S X X E NE 0018527 Ixora luzoniensis Merr. S X E NE 0018553 Ixora macrophylla Bartl. ex DC. T X NE NE 0018554 Ixora philippinensis Merr. S X X X NE NE 0018528 Tribe Lasiantheae Lasianthus attenuatus Jack S X NE NE 0018555 Lasianthus biflorus (Blume) M. Gangop.& Chakrab. S X NE NE 0018556 Lasianthus hirsutus (Roxb.) Merr. S X NE NE 0018557 Tribe Morindeae Morinda citrifolia L. T X NE 0018529 Tribe Mussaendeae NE/ acuminatissima Merr. T X E 0018558 VU* Mussaenda benguetensis Elmer T X E NE 0018559

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Distribution Proposed Accession Species Habit Mt. Endemicity KPNP MINWFR status number Lammin Mussaenda philippica A. Rich. var. philippica T X X E LC 0018530 Tribe Naucleeae orientalis (L.) L. T X X NE LC 0018531 Neonauclea bartlingii var. cumingiana (S. Vidal) T X X E LC 0018532 Ridsdale Neonauclea reticulata (Havil.) Merr. T X X NE NE 0018544 lanosa Wall. L X NE NE 0018560 Uncaria longiflora(Poir.) Merr. L X NE NE 0018579 Uncaria perrottetii (A.Rich.)Merr. L X E NE 0018561 Tribe Ophiorrhizeae Ophiorrhiza argostemmoides Elmer H X E NE 0018562 Ophiorrhiza cf. involucrata H X E NE 0018563 Ophiorrhiza oblongifolia DC. H X E NE 0018564 Ophiorrhiza oblongilimba Merr. H X E NE 0018565 Tribe Paederieae Paederia foetida L. L X X X NE NE 0018533 Tribe Psychotrieae Psychotria sp. 1 S X 0018566 Psychotria sp. 2 T X 0018570 Psychotria ixoroides Bartl. ex DC. L X E NE 0018567 Psychotria luzoniensis (Cham.& Schltdl.) Fern.- S X X X E NE 0018535 Vill Psychotria manillensis Bartl. ex DC. S X NE NE 0018568 var. subsessiliflora Psychotria membranifolia Bartl. ex DC. S X NE NE 0018569 Psychotria pilosella Elmer S X E NE 0018571 Psychotria subsessilifloravar. subsessiliflora Elmer S X E NE 0018572 Psychotria tayabensis var. castanea (Merr.) Sohmer S X X E NE 0018545 & A.P.Davis Tribe Spermacoceae Exallage cristata (Willd.) Nandikar & K.C.Kishor H X NE NE 0018573 Oldenlandia corymbosa L. H X X X NE NE 0018536 Spermacoce sp. H X 0018574 Spermacoce ocymoides Burm. f H X X NE NE 0018537 Spermacoce remota Lam. H X X X NE NE 0018538 Tribe Urophylleae NE/ Antherostele callophylla Bremek. T X E 0018575 CR* Praravinia sp. T X 0018576 Urophyllum caudatum Merr. S X E NE 0018577 Tribe Vanguerieae Canthium horridum Blume S X NE NE 0018546 Canthium sp. S X 0018539 Kanapia monstrosa (A.Rich.) Arriola & Alejandro T X X E NE 0018540 Pysdrax cf. gynochthodes T X NE NE 0018578 Pyrostria subsessilifolia (Merr.) Arriola & S X E NE 0018541 Alejandro Pyrostria triflora Arriola, Calaramo & Alejandro S X X X E NE 0018542 Total 16 47 19

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Figure 3. Number of collected Rubiaceae species from the surveyed sites in Ilocos Norte by growth habit and according to tribe, genera and species: A) number of species per growth habit (Tr – ; Sh – shrub; He – herb; Li – liana); B) proportion of tribe, genera, and species.

Distribution of Species with Taxonomic Notes on Philippine Endemics The genus Psychotria under the tribe Psychotrieae had the highest number of species found in our survey. The genus can be easily distinguished from other genera of Rubiaceae by having terminal inflorescences, small corolla, anthers inserted within the ring of corolla throat hairs, caducuous stipule, pyrenes that are usually with ribs or ridges on the outer surface, two marginal preformed slits, and ruminate endosperm (Sohmer and Davis 2007). They are chiefly distributed in the tropics and 112 species are currently recognized in the country where almost all are identified as endemic. However, due to rapid habitat losses, it is assumed that almost half are already extinct (Sohmer 2001). In this study, we documented the following Psychotria species: P. ixoroides Bartl. ex DC. (Figure 4A), P. luzoniensis (Cham. & Schltdl.) Fern.- Vill (Figure 4B), P. manillensis Bartl. ex DC (Figure 4C), P. membranifolia Bartl. ex DC. (Figure 4D), P. pilosella (Figure 4E), P. subsessiliflora var. subsessiliflora Elmer (Figure 4F), P. tayabensis var. castanea (Merr.) Sohmer & A.P.Davis (Figures 4G, 11C, and 11D) and two unidentified Psychotria species (Figures 4H and 4I). These are distributed at various elevations from 100 masl up to 1000 masl, but the majority are found in the vegetation of KPNP as shrubs or small trees. One of the earliest species described in the country in 1830 is P. ixoroides (Sohmer and Davis 2007). It is easily recognized by other Psychotria species in the area by Figure 4. A) Psychotria ixoroides, B) P. luzoniensis, C) P. its lianescent habit. Its flowers were not seen during manillensis, D) P. membranifolia, E) P. pilosella, F) P. the survey but the fruit is obovoid, 4 mm long, and subsessiliflora var. subsessiliflora, G) P. tayabensis var. monochotomous. Fruiting was observed in September castanea, H) Psychotria sp. 1, and I) Psychotria sp. 2. – in consonance with its recorded fruiting season during February, August, and September. This species was found in the primary forest of KPNP.

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Another species is P. luzoniensis, a widely distributed sub-coriaceous leaf blades that are broadly oblanceolate to Psychotria in the country, and found thriving in all the obovate measuring 16–18 x 8–10 cm. It has the broadest areas surveyed but commonly encountered in the forest leaves among the Psychotria species collected. No flowers over limestone of MINWFR. This species is a shrub with a were observed during the collection but infructescence height of about 2 m; narrowly elliptic to subobovate leaves; was noted to be trichotomous. In contrast, Psychotria 4-5-merous flowers; white or greenish-white to greenish- sp 2. is a tree about 3–4 m high with obovate to elliptic yellow corolla; and orange fruits. The species was flowering leaves measuring 4–6 x 3–4 cm, attenuating apex, obtuse and fruiting when collected in early-February. to acute base, and trichotomous infructescence with ovoid and smooth fruits measuring 4–5 mm. Observed to occur in KPNP, P. pilosella exists as a shrub measuring 1–2 m high. Its stipule is valvate measuring Representatives from the species-rich genus Ixora L. 8–9 mm long. The leaf blades are obovate to narrowly were also encountered during the collection. This genus oblanceolate measuring 8 x 3 cm. consists of 34 species of woody trees and shrubs, with 25 known endemic species (Banag et al. 2017). Six Another species occurring in the tropical forest of KPNP species were collected, three of which are endemic to the is P. subsessiliflora var. subsessiliflora, which is a small Philippines – namely, I. bibracteata Elmer (Figure 5B), tree about 4–5 m tall, with glabrous stems, glabrous I. cumingiana S. Vidal (Figure 5C), and I. luzoniensis petioles 0.6–2.5 cm long, broad elliptic leaf blades to Merr (Figure 5D). broadly obovate, infructescence with short main axis, and obovoid fruit 7 –9 mm long, smooth, and red to black at Ixora bibracteata is found along the forested ridges at low maturity, distinctly wrinkled when dried, calyx limb and to medium altitude in KPNP. It is a shrub 2–3 m tall with lobes persistent but not obvious, pedicels absent. caducous stipules and truncate sheath. It has subsessile leaves measuring 10 x 3.5 cm with oblanceolate blades, Two other interesting Psychotria species were encountered membranaceous texture, shortly acuminate apex, and in KPNP. Psychotria sp. 1 is a shrub about 2–3 m high with cuneate base. It has solitary and sessile flowers, as well as

Figure 5. A) Ixora cf. auriculata, B) I. bibracteata, C) I. cumingiana, D) I. luzoniensis, E) I. macrophylla, and F) I. philippinensis.

494 Philippine Journal of Science Batuyong et al.: Rubiaceae Species in Ilocos Vol. 150 No. S1, Special Issue on Biodiversity Norte, Northwestern Luzon, Philippines fruits measuring 6 x 8 mm that are greenish and turning red elevation. Among the three species, only L. biflorus is when ripe, globose in shape, and with a persistent calyx. present at 1050 m. The Philippine Lasianthus was first enumerated by Merrill (1923), which comprises 15 species Another widely distributed endemic Ixora that was – 11 of which are endemic. In the recent Malesian revision collected in KPNP and MINWFR is I. cumingiana. It is of Lasianthus, Zhu et al. (2012) recognized a total of 22 a shrub 3 m tall with persistent stipules and a triangular Philippine Lasianthus species, of which five are endemic sheath measuring 2 mm long. Its leaves have 1 cm long and one to include another recently described new species petioles, subelliptic blades, elliptic-oblong to ovate shape L. halconensis (Arshed and Alejandro 2016). measuring 8 x 3 x 10 cm, and acute to cuneate base. Its pedicillate flowers form triads, each having an ovary and Ophiorrhiza L. is a species-rich genus, with 319 species green to red calyx. The fruit is globose that measures 8 x distributed in the tropical and subtropical forests of Asia 9 mm and appears green turning purple when ripe. and Pacific Islands. Most recently, Pelser et al. (2011 onward) recorded 30 species in the Philippines, of which One of the species encountered in KPNP at an elevation 28 are endemic to the country. Four species were collected of 100–450 masl is I. luzoniensis. It is a shrub 3 m tall in KPNP: O. argostemmoides Elmer (Figure 7C), O. with persistent stipules and a triangular sheath. Its leaves oblongifolia DC. (Figure 7A), and O. oblongilimba have 0.2 cm long petioles, oblong-lanceolate leaf blades Merr. (Figure 7B). Ophiorrhiza cf. involucrata (Figure measuring 15 x 2.5 cm, chartaceous texture, drying pale D) needs further morphological examination. These brown color on both sides, shortly acuminate apex, and species were found along streams at low to medium acute base. Its fruit is subglobose measuring 4 x 3 mm altitudes and in areas with shade and moisture and no and is green in color. constant disturbances. As observed, members of this The Ixora cf. auriculata collected – being a shrub with genus range from minute herbs about 3–10 cm high (O. sessile leaves having linear-oblong blades, dull green color argostemmoides) to larger subshrubs having lanceolate above and paler underside, and acute apex – was found at to oblanceolate leaves (O. oblongifolia, O. oblongilimba, low elevation in the primary forest of KPNP. However, O.cf. involucrata). The presence of O. argostemmoides the collection of its reproductive structures is needed to and O. oblongifolia are proofs of an extended geographic further confirm its identity. distribution beyond their type locality. Three erect suffrutescent species from the genus Lasianthus were thriving in KPNP. The collected species are L. attenuatus Jack (Figure 6A), L. biflorus (Blume) M.Gangop. & Chakrab. (Figure 6B), and L. hirsutus (Roxb.) Merr. (Figure 6C). They have axillary inflorescences having one to many flowers that are sessile to pedunculate. The flowers seen are white. Fruits are blue or black, small, pulpy and fleshy, and glabrous to pubescent outside. Although these species are regarded to be widely distributed, these species are new records in the province, inhabiting the shaded and moist primary forest of KPNP from low elevation ascending to medium

Figure 7. A) Ophiorrhiza oblongifolia, B) O. oblongilimba, C) O. argostemmoides, and D) O. cf. involucrata. Photos taken by M.A. Batuyong and M.A. Calaramo.

Six species from the tribe Naucleeae were collected belonging to genera Nauclea L., Neonauclea Merr. and Uncaria Schreb. They can be easily differentiated from other genera within the family by spherical inflorescence (Ridsdale 1978a). Neonauclea comprises 16 species in the country – of which one endemic species, Neonauclea Figure 6. A) Lasianthus attenuatus, B) L. biflorus, and C) L. bartlingii var. cumingiana (S. Vidal) Ridsdale (Figure hirsutus. Photos taken by M.A. 8A) – is collected in the surveyed sites near streams at Batuyong and M.A. Calaramo. lowland to medium elevation and along the trails of Mt.

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Figure 8. A) Neonauclea bartlingii var. cumingiana, B) N. reticulata, C) Uncaria lanosa, D) U. perrottetii, and E) U. longiflora. Photos taken by M.A. Batuyong and M.A. Calaramo.

Lammin. The species occurs to be a shrub to small tree. The widespread species Wendlandia luzoniensis DC. – Although the two other species from the genus Uncaria, noted to be a small- to a medium-sized tree about 5 m high U. lanosa Wall. and U. longiflora (Poir.) Merr. (Figures having terminal paniculiform inflorescence and tubular 8C and D) are considered not endemic, they still contribute white corolla – is also found occurring in Mt. Lammin to the forest canopies at KPNP where they were found and MINWFR. On the other hand, the endemic species thriving. These two species are easily recognized being Wendlandia philippinensis Cowan thrives in KPNP along woody lianas and with the presence of hooks formed from the lowland elevation (Figure 9C). reduced, modified branches (Ridsdale 1978b). Other endemic species – such as Mussaenda acuminatissima The tribe Spermacoceae were also represented by five Merr. (Figure 9B), Pyrostria subsessilifolia (Merr.) Arriola species from the following four genera – namely, Exallage & Alejandro (Figure 9E), and Urophyllum caudatum Merr. Bremek, Hedyotis L., Spermacoce L, and Oldenlandia L. (Figure 9D) – were collected in the undisturbed area within These species include Exallage cristata (Willd.) Nandikar KPNP at elevations of 400–700 masl. On the other hand, & K.C. Kishor, Spermacoce ocymoides Burm. f, S. remota Timonius ternifolius (Bartl. ex DC.; Figure 9F) occurs in Lam., Spermacoce sp., and Oldenlandia corymbosa L. – both KPNP and MINWFR. all of which are non-endemic. Some endemic species to Ilocos Norte such as Pyrostria The Philippine endemic genera – Antherostele Bremek. triflora Arriola, Calaramo & Alejandro (Figures 11G and and Kanapia Arriola & Alejandro – are recorded in the 11H) and Antirhea microphylla (Bartl. ex DC.) Merr. Province. (Figures 11A and 11B) were observed in areas exposed to human influence such as along the access road within the The scrambling shrub species, Kanapia monstrosa (A. protected area of MINWFR where tourists and picnickers Rich.) Arriola & Alejandro (Figure 9A), was collected in frequently visit. MINWFR and also thrives in KPNP. This species is about 4 m high with puberulous stem, as well as chartaceous leaf Lastly, the thorny species Canthium horridum Blume blades having lanceolate shape measuring 10 x 4.5 cm, dark (Figure 10D) and one interesting species assigned under green color at the dorsal side and pale green at the ventral the same genus (Figures 10A, 10B, and 10C) were also side, attenuate apex, and acute base. Its stipules are 4 mm collected in Mt. Lammin and MINWFR, respectively. This long. Inflorescences are axillary that are paired at each possibly undescribed species is currently being examined node, highly dense, and compactly branched; its peduncle to establish its identity because several of its observed is 4 mm long and its glabrous flowers are pentamerous. morphological characters do not fit any described species. The fruits are 1(2) seeded, ellipsoid in shape, and 0.9 cm in length. Only three mature individuals were observed Ilocos Norte Endemics and Their Taxonomic Notes from the areas where this species occurred. Flowering was observed in March and fruiting in April–May. • Tribe Guettardeae

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Figure 9. A) Kanapia montrosa, B) Mussaenda acuminatissima, C) Wendlandia philippinensis, D) Urophyllum caudatum, E) Pyrostria subsessilifolia, and F) Timonius ternifolius. Photos taken by M.A. Batuyong and M.A. Calaramo.

Figure 10. Canthium sp. [A) habit; B) fruiting and flowering branch; C) close-up of the leaves showing the thorns]; D) Canthium horridum. Photos taken by M.A. Batuyong and M.A. Calaramo.

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Figure 11. Antirhea microphylla [A) fruiting branch; B) flower], Psychotria tayabensis var. castanea [C) fruiting branch; D) close-up of the mature fruit], Antherostele callophylla [E) habit; F) flower], Pyrostria triflora [G) flowering branch; H) close-up of the fruit]. Photos taken by M.A. Batuyong and M.A. Calaramo.

○ Antirhea microphylla (Bartl. ex DC.) Merr. observed in March–May (Figures 11A and 11B) Conservation assessment: Based on the Brief description: shrub, 1–2 m tall, stem dark IUCN red list categories and criteria v14 to dark brown, erect, slender branches; leaves (2019), A. microphylla is considered belonging very small, 1–2.5 x 1–2 cm, prominent nerves, to the category Vulnerable VU B1, B2 a,b(iii) usually the presence of anthocyanine in leaves – given its restricted distribution and confined especially in dry places; flowers very minute, area of occupancy. Besides, human land use, terminal to subterminal, tubular with white to infrastructure developments within the area, pinkish flowers 1.5–2.5 x 3 mm; fruit obovoid, and encroachment by humans are observed 0.5–0.7 x 0.4–0.6 mm, turning reddish-brown to be very common. to black when ripe Distribution: found in lowland elevations • Tribe Psychotrieae from 100–450 masl and observed to have ○ Psychotria tayabensis var. castanea (Merr.) restricted distribution on the forest over Sohmer & A.P.Davis (Figures 11C and 11D) limestone of MINWFR Brief description: Shrub ca. 1–2 m tall, Phenology: flowering and fruiting when glabrous throughout; stipules 5–7 mm collected in early-November; fruiting also long; leaves glabrous, narrowly elliptic to

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oblanceolate, 6–8.5 x 1.2–1.6 cm, attenuate enclosing the young inflorescence, pedicels base, apex acuminate; fruits sessile and erect, 5 mm long at flowering, persistent; obovoid, about 5–7 mm long male flowers calyx glabrous, tube 1 mm Distribution: this species was found sparsely long, lobes broadly triangular, 0.2 × 0.4 mm; distributed with few mature individuals in corolla 4-merous, white, glabrous outside, KPNP and Mt. Lammin at ca. 450–900 masl. tube tubular, 1 mm long; stamens attached Phenology: no flower seen during the to corolla tube adjacent to the throat, anthers collection; fruiting observed in February and narrowly ovate, 0.3 mm long; fruits small with November. longitudinal ridges; turning bright yellow- Conservation assessment: according to orange at ripening stage. the IUCN red list category v14 (2019), this Distribution: occur in all the areas surveyed species is Endangered EN B2 a,b(iii); B2: at 200–450 masl the area of occupancy is estimated to be less Phenology: flowering in April–June and than 500 km2; a: fragmented location; b(iii), October–November; fruiting in May–August the continuing decline in the area, extent, and December–January (in rare cases) and quality of habitat is inferred due to the Conservation assessment: although the observed anthropogenic activities. species P. triflora was found in all the areas surveyed, having such a restricted • Tribe Urophylleae distribution and an unpredictable localized ○ Antherostele callophylla Bremek. (Figures 11E habitat degradation would put this species at and 11F) risk. Thus, following the IUCN guidelines Brief description: trees 4–5 m tall, bark light (v14), we also proposed and placed the species brownish-gray, smooth; stipules ovate, 6–7 as Vulnerable VU B2 a,b (iii). x 4–5 mm, recurved; leaves glabrous, blades elliptic, 10.5–13.5 × 4–6 cm, coriaceous, base Endemism and Conservation Status acute to rounded, apex acuminate; inflorescence A total of 27 endemic species were recorded in all the axillary; fruit subglobose 13–14 x 13–15 mm, sites. KPNP harbors most of the endemic with 23 species green at maturity turning orange when ripe (Table 1). Remarkably, four of which are known to have Distribution: found in Mt. Palemlem at an natural habitat confined in the province. These include A. elevation of 450–750 masl callophylla, P. tayabensis var. castanea, P. triflora, and Phenology: flowering and fruiting when A. microphylla, but the latter has an extended distribution collected in May in Ilocos Sur. Noteworthy to mention that two Philippine Conservation assessment: based on the actual endemic genera, Antherostele and Kanapia, were also evaluation and following the IUCN Guidelines recorded in the surveyed sites. v14 (2019), herein we also proposed A. callophylla as Critically Endangered CR Threatened species were also documented. One species, B2a,b(iii); B2: the area of occupancy is W. philippinensis, is classified as Endangered (IUCN estimated to be less than 10 km2; a: is known v.4.1) in the IUCN red list of threatened species. However, to exist at only a single location; b(iii): the following the most recent recommendations issued by continuing decline in the area, extent and/ DENR DAO 2017-11, one is Critically Endangered (A. or quality of habitat is inferred due to the callophylla) and one Vulnerable (M. acuminatissima). It is observed logging activities in the area of interesting to note that these two species are also endemic. occupancy. Based on our fieldwork and assessment on the status • Tribe Vanguerieae of the four endemic species in the province following ○ Pyrostria triflora Arriola, Calaramo & the category of IUCN v14 (2019), we proposed the Alejandro (Figures 11G and 11H) conservation status for A. callophylla as Critically Brief description: shrub, 1.0 m high, branches Endangered. Initially, the same category was provided terete and glabrous; leaves lanceolate, 6 × 3 by Obico and Alejandro (2012) in their preliminary cm, glabrous on both sides, apex attenuate, assessment. On the other hand, P. tayabensis var. base attenuate; stipules ovate to triangular, castanea is Endangered. According to Sohmer and 3 × 1 mm, glabrous on both sides; male Davis (2007) – in their preliminary assessment of this inflorescence axillary 1.0 mm long peduncles, species – it was last collected in 1975, which has led to 3-flowered; peduncular bracts present, 3.5 its status as Endangered. At present, we also categorized mm long, triangular, glabrous on both sides, A. microphylla and P. triflora as Vulnerable.

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This suggests immediate monitoring and management for of Ilocos Norte, CENRO–Northern Ilocos Norte and their protection to ensure the continued survival of the CENRO–Central, Southern, and Eastern Ilocos Norte, remaining population in the area. One of the initiatives LGU-Adams, Pagudpud, Pasuquin, and Piddig, the to address this concern is the ex situ conservation of plant KPNP, and MINWFR Protected Area Management collections to include some of the endemic species of Board members for the endorsement and GP allowing us Rubiaceae being maintained at the NUEBG (GP-2013-01 to perform the study. To MINWFR PASu Cielo Acacio and GP -2013-02). and KPNP PASu Cynthia Cacactin for their assistance during the fieldworks. Lastly, acknowledgment is due to Joey Nazareno and For. Joseph Leweilyn Acang for providing the map. CONCLUSION The Province of Ilocos Norte harbors several Rubiaceae species. Initially, 57 species were collected belonging to REFERENCES 28 genera representing 15 tribes. This number of species comprises about 10.36% of the total number of Rubiaceae ALEJANDRO GJD, LIEDE-SCHUMANN S. 2003. The species in the country. Twenty-seven (27) species are Philippine Rubiaceae genera. Updated synopsis in Philippine endemics, and four species are endemic to INTKEY databases of the DELTA system. Blumea 48: the province. Among the sites surveyed, the tropical 261–277. doi: 10.3767/000651903X674964 evergreen lowland rain forest of KPNP had the highest ALEJANDRO G. 2007. The current status of the Philip- number of recorded species. Expectedly, these collections pine Rubiaceae. Philippine Journal of Systematic Biol- will be increased when other areas in Ilocos Norte will ogy 1(1): 47–60. https://doi.org/10.3860/pjsb.clil.908 be surveyed. ALEJANDRO GJD, MEVE U, UY M, MOULY A, THIV As regards conservation, one is listed as Endangered M, LIEDE-SCHUMANN S. 2010. Molecular support (IUCN red list of threatened species), one Critically of the classification of Greeniopsis Merr. in Aleisan- Endangered, and one Vulnerable (DENR AO 2017-11). An thieae (Rubiaceae), with a revision of the genus. Taxon update on the assessment of the local conservation status 59(5) : 1547–1564. of the endemic species in the province is also provided based on IUCN criteria: one as Critically Endangered, ALEJANDRO GJD, MEVE U, MOULY A, THIV M, one Endangered, and two Vulnerable. LIEDE-SCHUMANN S. 2011. Molecular phylogeny and taxonomic revision of the Philippine endemic Vil- Also, we found several species that were recorded laria Rolfe (Rubiaceae). Plant Systematics & Evolution previously only in their type localities outside the 296: 1–20. doi: 10.1007/s00606-011-0472-9 province. Hence, the documentation of these species in the province contributes to the number of taxa that have ARRIOLA AH, CAMACHO PD, CALARAMO MA, been re-collected and represent significant data both ALEJANDRO GJD. 2015. Pyrostria triflora, a new for the province and their geographic distribution in the species of Vanguerieae (Rubiaceae) from Luzon, country in general. Our new data on these endemic taxa Philippines. Bangladesh J Plant Taxon 22(1): 55–58. are particularly significant as a basis to come up with ARRIOLA AH, PARAGUISON LD, ALEJANDRO GJD. their recent proposed conservation status. Moreover, for 2016. Kanapia (Vanguerieae): a new endemic genus of the continual assessment and monitoring of conservation Philippine Rubiaceae. Plant Syst Evol. DOI: 10.1007/ initiatives of these species and in sustainably managing s00606-016-1317-5 these vulnerable areas. ARSHED MJ, ALEJANDRO G. 2016. A new Philippine endemic species and new records of Lasianthus (La- siantheae, Rubiaceae). Phytotaxa 288(3). DOI: http:// ACKNOWLEDGMENTS dx.doi.org/10.11646/phtotaxa.288.3.12 The first author is grateful to the Commission on Higher BANAG C, MOULY A, ALEJANDRO G, BREMER B, Education and Mariano Marcos State University for the MEVE U, GRIMM G, LIEDE-SCHUMMAN S. 2017. scholarship grant. The authors would also like to thank Ixora (Rubiaceae) on the Philippines-cross-road or the directors and curators of CAHUP, HNUL, PNH, and cradle? BMC Evolutionary Biology 17: 131. https// USTH for granting access to the herbarium collections. doi.org/10.1186/s12862-017-0974-3 Acknowledgment is also given to the DENR-Region 1, BATUYONG MAR, CALARAMO MA, ALEJANDRO Provincial Environment and Natural Resources Office GJD. 2020. A checklist and conservation status of

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