REINWARDTIA Vol. 21. No. 1. pp: 13‒17 DOI: 10.55981/reinwardtia.v21i1.4268 13 A NEW VARIETY OF CANTHIUMERA GLABRA (RUBIACEAE: VANGUERIEAE) Received December 1, 2021; accepted April 16, 2022 RIDHA MAHYUNI Herbarium Bogoriense, Research Center for Biosystematics and Evolution, National Research and Innovation Agency/Badan Riset dan Inovasi Nasional (BRIN), Cibinong Science Center, Jln. Raya Jakarta Bogor Km. 46, Cibinong 16911, Bogor, Indonesia. Email: ridhamahyuni@gmail.com TATIK CHIKMAWATI Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680, Indonesia. Email: tchikmawati@yahoo.com. NUNIK SRI ARIYANTI Department of Biology, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680, Indonesia. Email: nuniksa@gmail.com ANNE KUSUMAWATY Directorate of Scientific Collection Management, National Research and Innovation Agency/Badan Riset dan Inovasi Nasional (BRIN), Cibinong Science Center, Jln. Raya Jakarta Bogor Km. 46, Cibinong 16911, Bogor, Indonesia. Email: annekusuma01@gmail.com ABSTRACT MAHYUNI, R., CHIKMAWATI, T., ARIYANTI, N. S. & KUSUMAWATY, A. 2022. A new variety of Canthiumera glabra (Rubiaceae: Vanguerieae). Reinwardtia 21(1): 13‒17. — Canthiumera glabra var. laxiflora (Rubiaceae: Vanguerieae), a new variety from Java and Sumatra is described. The new variety differs from the typical variety in having laxly branched inflorescences and is restricted to south Sumatra (Lampung) and southwestern Java. Key words: Canthium glabrum, Indonesia, inflorescence form, Malesia. ABSTRAK MAHYUNI, R., CHIKMAWATI, T., ARIYANTI, N. S. & KUSUMAWATY, A. 2022. Varietas baru Canthiumera glabra (Rubiaceae: Vanguerieae). Reinwardtia 21(1): 13‒17. — Canthiumera glabra var. laxiflora (Rubiaceae: Vanguerieae), varietas baru yang berasal dari Jawa dan Sumatra telah dipertelakan. Varietas baru ini dibedakan dari kelonggaran cabang perbungaannya dan memiliki sebaran terbatas di Sumatra bagian selatan (Lampung) dan Jawa bagian barat daya. Kata kunci: Bentuk per bungaan, Canthium glabru m , Indonesia, Malesia. INTRODUCTION The tribe Vanguerieae is strictly defined by morphological characters such as axillary inflorescences, valvate corolla lobes, recessed stigmatic base, and ovaries with a solitary pendulous ovule. However, one of the problematic groups within Vanguerieae is the Canthium alliance, in which members of the alliance were distinguished in having characters such as axillary spines, presence of brachyblast, tufts of hair in stipules, unisexual or bisexual flowers, types of inflorescenses, shapes of calyx tube, and presence of hairs on corolla tubes. Bridson (1992) laid out the foundation work on Vanguerieae, and subsequently Lantz & Bremer (2004) and Arriola et al. (2016) followed in utilising molecular and morphological data to distinguish groups within the Canthium alliance. Later, Wong et al. (2018) demonstrated that Canthium s.s. differed from other named genera in Vanguerieae through the presence of the axillary supernumery buds and spines. It should be noted that molecular studies by Lantz & Bremer (2004) and Razafimandimbison et al. (2009) lacked of materials from Southeast Asia and this rendered limited resolutions in their phylogenies. One of the segregate genera of Canthium s.l. is Canthiumera K.M.Wong & Mahyuni, and it is typified by Canthiumera glabrum (Blume) K.M.Wong & Mahyuni (Wong et al., 2018). In total, four species were recognised for Canthiumera and they can be distinguished based on the presence of hairs on leaf margin and http://dx.doi.org/10.14203/reinwardtia.v19i1.3850 REINWARDTIA 14 [VOL.21 Fig. 1. Holotype of Canthiumera glabra var. laxiflora (M. Jacobs 8297). MAHYUNI et al.: A new variety of Canthiumera glabra (Rubiaceae: Vanguerieae) 2022] 15 morphological characteristics on floral parts (shape of corolla tube, length of calyx, and hairs on style) and shapes of pyrene. Canthiumera glabrum is a species distributed in Java, Bali, and Sumbawa, and it has distinct morphological characteristics from the other species, namely Canthiumera robusta, C. siamensis, and C. neilgherrensis, by its 1‒1.5 mm long calyx, corolla lobes about the same length as the corolla tube, and a pubescent style. While sorting through materials of Canthiumera glabrum at Herbarium Bogoriense, we came across specimens with distinct differences in inflorescence characteristics but otherwise matches well with other materials of Canthiumera glabrum. Based on this distinct morphological character, we hereby describe a new variety to accommodate these materials from Lampung (south Sumatra) and Ujung Kulon (extreme West Java). A description of this new variety and a map of its distribution are provided here. MATERIALS AND METHODS This study was conducted following a standard protocol for taxonomic studies in which morphological characteristics of vegetative and generative part were observed from preserved herbarium specimens at Herbarium Bogoriense (BO), Forest Research Institute of Malaysia (KEP), Sandakan Herbarium (SAN), Sarawak Forest Department (SAR), and Singapore Botanic Gardens (SING). RESULTS AND DISCUSSION Distribution of Canthiumera glabra includes Java, Bali, and Sumbawa. We are unable to establish if C. glabra var. glabra occurs in Sumatra. In general, morphological characters between C. glabra var. glabra and C. glabra var. laxiflora largely overlaps, with the exceptions of fruit pedicels of C. glabra var. laxiflora which is Fig. 2. A & B. Canthiumera glabra var. laxiflora. A. Sparse inflorescence type observed from M. Jacobs 8297. B. Sparse inforescence type observed from Nengah Wirawan 197. Drawn by Anne Kusumawaty. C. Dense inflorescence type of Canthiumera glabra var. glabra. (Koorders 26702b, Koorders & Valeton, Atlas der Baaumaten von Java). REINWARDTIA 16 [VOL.21 shorter than those of the typical variety, i.e., ca. 0.5 mm long. The two varieties of Canthiumera glabra, namely Canthiumera glabra var. glabra and C. glabra var. laxiflora can only be distinguished by their inflorescence type. In addition, Canthiumera glabra var. laxiflora is found to be restricted to southwestern Java and the Lampung district of Sumatra. Taxonomy Canthiumera glabra var. laxiflora Mahyuni, var. nov. — TYPE: INDONESIA, Sumatra, Province of Lampung, NW of Kota Agung, 5° 23’S, 104°25’E, 350–450 m, 9 May 1968, M. Jacobs 8297 (holotype BO!, isotype SING). Fig. 1. This new variety has laxly branched subumbellate cymes, peduncle 3–5 mm long branches, which has 1–2 mm long. Other specimens examined. INDONESIA, Java, Province of Banten; Ujung Kulon Nature Reserve, Mt. Pajung. 31 Dec 1963, Nengah Wirawan 167 (BO). Sumatra, Lampung, no specific locality, 6 Jul 1965, H.F. Sun 9935 (BO); Mt. Tanggamus, 27 April 1968, M. Jacobs 8075 (BO); Baturadja, Dec 1928, T. Hoelt s.n. (BO). Etymology. The new var iety epithet r efer s to the laxly branched inflorescences. Distribution. Endemic to southwester n J ava and south Sumatra (Lampung Province) (Fig. 4). At present, precise distribution of this new variety is unknown, apart from the present localities in Bukit Barisan National Park and the Ujung Kulon Nature Reserve. ACKNOWLEDGEMENTS This research was supported by the Ministry of Research, Technology and Higher Education of Indonesia. We would like to express our sincere thanks to the Keepers and Curators of the BO, KEP, SAN, SAR, and SING for permission to examine specimens under their care. Ridha Mahyuni would like to thank Prof. Dr. Mien A. Rifai and Prof. Dr. Tukirin Partomihardjo who supervised her doctoral studies. Dr. K. M. Wong (Singapore Botanic Gardens) is gratefully acknowledged for assistance with verification of the species and encouragements. Fig. 3. Flower buds of Canthiumera glabra var. glabra (Ridha, s.n., Bogor Botanic Garden). Photo by Ridha Mahyuni. MAHYUNI et al.: A new variety of Canthiumera glabra (Rubiaceae: Vanguerieae) 2022] 17 REFERENCES ARIOLLA, A. H., PARAGUISON, L. D. & ALEJANDRO, G. J. D. 2016. Kanapia (Vanguerieae): a new endemic genus of Philippine Rubiaceae. Plant Systematics and Evolution 302: 911–920. DOI: 10.007/s00606- 016-1307-5. BLUME, C. L. 1823. Catalogus van eenige der merkwaardigste zoo in-als uit-heemsche gewassen, te vinden in 's lands plantentuin te Buitenzorg. Batavia. 45 pp. BRIDSON, D. M. 1992. The genus Canthium (Rubiaceae-Vanguerieae) in tropical Africa. Kew Bulletin 47: 353–401. LANTZ, H. & BREMER, B. 2004. Phylogeny inferred from morphology and DNA data: Characterizing well-supported groups in Vanguerieae (Rubiaceae). Botanical Journal of Linnean Society 146: 257–283. RAZAFIMANDIMBISON, S. G, LANTZ, H., MOULY, A. & BREMER, B. 2009. Evolutionary trends, major lineages, and new generic limits in the dioecious group of the tribe Vanguerieae (Rubiaceae); insight into the evolution of functional dioecy. A nnals of the Missouri Botanical Garden 96:161–181. WONG, K. M., MAHYUNI, R., NG, X. Y. & NEO, L. 2018. Flora of Singapore Precursors, 8. Systematy of the new Southeast Asian genera Canthiumera and Dibridsonia (Rubiaceae: Vanguerieae), with notes on plant architecture and reproductive ecology. Reinwardtia 17(2): 101–124. Fig. 4. Distribution of Canthiumera glabra var. laxiflora. REINWARDTIA 18 [VOL.21