Villaria uniflora Arriola & Alejandro, 2013

Arriola, Axel H. & Alejandro, Grecebio Jonathan D., 2013, A new species of Villaria (Octotropideae, Rubiaceae) from Luzon, Philippines including its conservation status, Phytotaxa 111 (1), pp. 57-60 : 58-60

Villaria uniflora Arriola & Alejandro , sp. nov. ( Fig.1 )

Villaria uniflora differs from the other species of the genus by its uniflorous inflorescences, bracts narrowly acute at apex, infundibuliform calyx tube, triangular to ovate calyx lobes and lanceolate stigmatic lobes.

Type:— PHILIPPINES. Luzon, Cavite, Mounts Palaypalay and Mataas na Gulod National Park , Barangay Palicpican , Ternate , 14°12’18.47”N, 120°38’17.37”E, 660 m, 22 December 2011, A. H . Arriola , J. M . Roa & C. R . Tansiongco T026 (Holotype USTH, isotype PNH) .

Shrubs to small trees, 2.5–3 m tall; branches glabrous. Stipules triangular to ovate, 8–9.5 × 3–4 mm, keel prominent from the tip up to the lower one third, abaxially pilose on the upper one third of the keel, adaxially pilose at the base, margin sparsely ciliated; colleters numerous, brown, 0.2–0.8 mm long. Petioles 4.5–5.5 × 2–2.5 cm, puberulous; leaf blades lanceolate, 11.5–15.5 × 3.5–4.5 cm, base cuneate, apex caudate, coriaceous, glabrous throughout except for trichomes on the midrib adaxially; secondary veins 10–16 each side. Inflorescences axillary, uniflorous; pedicel 0.5–1.0 cm long (2–3 cm long in fruiting stage), puberulous; bracts triangular, 6.5–7 × 2.5–3 mm, apex narrowly acute, densely pilose on both sides, margins ciliated. Calyx tube infundibuliform, 3–3.5 × 4–4.5 mm, pubescent throughout; lobes triangular to ovate, 2–2.5 × 0.9–1.3 mm, green, pubescent outside, densely pilose at the base inside, margins ciliated. Corolla white, aestivation contorted to the left; tube infundibuliform, 3.5–4.5 × 2.5–3 mm, glabrous; lobes orbicular, 2–2.5 × 1–1.5 mm, glabrous outside, densely pilose on the base inside. Anthers sessile, partially exserted, linear, 2 × 0.8–1 mm, obtuse and ciliate at apex, sagittate at base, glabrous. Style 1–1.5 mm long; stigmatic branches lanceolate, 4– 4.5 × 1 mm, partially splitting when receptive, densely pilose outside, papillate inside. Ovary unilocular, biparietal; ovules numerous, horizontally oriented. Fruits globose, 7–7.8 × 3–3.5 cm, brown when ripe, puberulous, calyx persistent; stalk 3–4 mm long, puberulous. Seeds ovate to oblong, 3 × 1.5 mm, yellowish; exotesta cells fibrous.

Distribution and Habitat:— Villaria uniflora thrives in deep wooded ravines towards the summit of the mountain and stony grounds near a stream; from 440 to 660 m altitude.

Phenology:—Flowering from April to June, and fruiting from June to December

Conservation Status:—This species is restricted to Mounts Palaypalay and Mataas na Gulod National Park. Less that 10 mature individual were seen from the base of the mountain up to the deep forest ravines. For these reasons, we assessed V. uniflora as critically endangered species (CR B2), based on the IUCN (2001). Mounts Palaypalay and Mataas na Gulod National Park is the only remaining lowland evergreen forest in the province of Cavite. Although declared as national park there are settlements present and various anthropogenic pressures that threaten the area, such as agricultural expansion, forest fires, excessive collection of forest products and infrastructure development ( Birdlife International, 2013). Since V. uniflora is found only in the area this will further promote the conservation of this species as well as the protection of the national park.

Discussion:— Villaria uniflora resembles V. glomerata because of its lanceolate leaf blades; however, V. uniflora can be distinguished from the other species of the genus by its strictly uniflorous inflorescences, bracts narrowly acute at apex, infundibuliform calyx tube, triangular to ovate calyx lobes, and lanceolate stigmatic lobes. These features were not observed in any Villaria species from the work of Alejandro et al. (2011).

Figures

FIGURE 1. Villaria uniflora. (from the holotype). A. Flowering and fruiting branch. B. Flower. C. Open corolla. D. Ovary in longitudinal section. E. Style. F. Fruit, longitudinal section. G. Seed. Drawn by N. Diego.