Sonerila bokorense S.H. Cho and Y.D. Kim, 2015

Sonerila bokorense S.H. Cho and Y.D. Kim View in CoL , sp. nov. ( Figs. 1 View FIGURE 1 & 2 View FIGURE 2 )

Sonerila bokorense is similar to S. calophylla , but it is distinguished by having aggregated tubercles, narrower leaves, presence of glandular trichomes on the pedicels, hypanthium, abaxial mid-vein of the petals, and capsules.

Type:— CAMBODIA. Kampot: Bokor National Park , 10°37′25.6″N, 104°01′36.9″E, 1101 m, 20 October 2010, Cho et al. CB-1730 (holotype HHU! GoogleMaps , isotype KB! GoogleMaps ).

Perennial herb, erect, (5–) 10–30 cm high, 1 (or rarely 2) shoot from rhizome. Rhizome with aggregated tubercles, globose, 1–2 cm in diameter. Stems 4-angled, slightly winged, sparsely pubescent, tinged purplish and with scattered lenticels, internodes to 7.6 cm long, sparsely branched. Leaves simple, opposite, mostly clustered at upper-most nodes, membranous; stipules lacking; petioles 0.2–2.2 cm long; leaf blade elliptic to ovate (2.2:1 to 3:1), 1.7–5.8 × 0.8–2.0 cm, abaxial surface with scattered seta on veins, adaxial surface setose between veins or near margin, setae 0.4–0.5 mm long, sometimes with white spots or patches along the midrib, secondary veins pinnate, 3 to 6 on each side of mid-vein, apex acute, base attenuate to rounded, margin serrulate with each tooth having a terminal seta. Inflorescences terminal, pedunculate, 1 to 5 scorpioid cymes with 3 to 11 flowers; bracts small, subulate, 0.7–1.3 mm long, caducous; peduncles 2.5–7.0 cm long, in fruit 3.0– 10.7 cm long, subangular, sparsely pubescent. Pedicels ca. 2.5 mm long, with glandular trichomes. Flowers, 3-merous. Hypanthium campanulate, 3-angled, 6-ribbed, 4.5–5.0 mm long, 1.6–1.9 mm in diam., with glandular trichomes ca. 0.5 mm long. Calyx lobes broadly triangular, 1.0– 1.2 mm long, apex acute, green. Petals 3, thin, 9.5–11 × 4.0–5.0 mm, ovate-obovate, apex acute to acuminate, pink to purplish pink, abaxially with glandular trichomes on mid-vein, adaxially glabrous. Stamens 3, filaments distinct, 4.8–6.8 mm long, glabrous, pinkish; anthers 5.4–6.0 mm long, lanceolate, deeply cordate to sagittate at the base, apex acute, yellow, poricidally dehiscent. Ovary inferior, urceolate, apex with a membranous 3-lobed crown, ovules numerous, placentation axillary; style filiform, 1.0– 1.3 cm long, glabrous, pink; stigma apiculate. Fruit a capsule, campanulate, 5–5.4 × 3–4 mm, crown woody and exserted from calyx, 6 longitudinal ribs, with glandular trichomes. Seeds cuneate, numerous, 0.93–0.95 mm long, light brown, papillate.

Phenology:—Flowering in July to October; fruiting in September to November.

Distribution and habitat:— Sonerila bokorense is a rare, local endemic restricted to the Bokor National Park in southwestern Cambodia. It grows in dwarf forests [dominated by Dacrydium elatum (Roxburgh) Wallich ex Hooker (1843: 144) , Rhododendron moulmainense Hooker (1856: 4904) , Lithocarpus leiophyllus A. Camus (1938: 181) ] and on rocks and in crevices [with Acronychia pedunculata (Linnaeus) Miquel (1861: 532) , Ardisia smaragdina Pitard (1930: 841) , Rhodomyrtus tomentosa (Aiton) Hasskarl (1842: 35) , Syzygium bokorense W.K. Soh & J. Parnell (2011: 557) ] on a sandstone plateau (950–1100 m). This species has a very restricted distribution.

Etymology:—The specific epithet of the new species refers to Bokor, the mountain where the species is endemic to.

Additional specimens examined:— CAMBODIA. Kampot: Bokor National Park , 10°37′27.7″N 104°01′20.9″E, 1060 m, 20 October 2010, Cho et al. CB-1775 ( MO!, HHU!) GoogleMaps , 10°37′24.29″N 104°01′36.42″E, 1063 m, 27 November 2014, Cho et al.CB-2961 ( HHU!) GoogleMaps , 10°39′32.2″N 104°03′04.7″E, 922m, 28 November 2014, Cho et al. CB-2962 ( HHU!) GoogleMaps , 10°39′22.3″N 104°03′54.4″E, 948 m, 04 November 2012, Won et al. 8251 ( DGU!) GoogleMaps , 10°37′39.9″N 104°02′36.7″E, 1013 m, 01 July 2012, Won et al. 8396 ( DGU!) GoogleMaps , 10°39′16.95″N 104°04′20.57″E, 965 m, 28 November 2014, Kim & Jo TCA2014-1739 ( KUS!) GoogleMaps

Notes:— Sonerila bokorense resembles S. calophylla ; however, S. bokorense has glandular trichomes on the pedicels, abaxial midvein of the petals, hypanthium, and capsules. It also has comparatively narrower leaves, and aggregated tubercles ( Table 1 View TABLE 1 ).