Psydrax puberula Arriola and Alejandro, 2013

Arriola, Axel H. & Alejandro, Grecebio Jonathan D., 2013, A new species of Psydrax (Vanguerieae, Rubiaceae) from Luzon, Philippines, Phytotaxa 149 (1), pp. 27-30 : 28

Psydrax puberula Arriola and Alejandro , sp. nov. ( Fig. 1 )

Psydrax puberula is distinguished from other species of the genus by its puberulent, compound-umbellate inflorescences with 14–25 flowers, as well as a puberulent fruit pedicel and fruit.

Type: — PHILIPPINES. Luzon, Camarines Sur Province: Municipality of Caramoan, Barangay Guijalo , 13 o 47.8’N, 123 o 40.0’E, 623 m, 11 February 1995, Reynoso, Sagcal, & Fuentes 14758 (holotype L!, isotype PNH!)

Tree, 5–7 m tall; branches glabrous and terete. Stipules glabrous on both sides, truncate to triangular, base 2–4 mm, apex 10–12 mm, keel very prominent on the abaxial side. Petioles 1.0–1.5 × 0.3–0.5 cm, glabrous; leaf blades elliptic, 7–9.5 × 4.5–5 cm, base cuneate, apex cuspidate, coriaceous, glabrous throughout, glossy; lateral nerves 4–5 on each side of the midrib, very prominent with their white tinge, domatia absent. Inflorescences axillary, 14–25-flowered, arranged in compound umbels, puberulent; peduncle 2–4 mm, puberulent; pedicel 1.0– 1.8 cm, puberulent. Calyx tube infundibuliform, 2–3 × 2.0– 2.5 mm, puberulent; lobes triangular 1.5–2.0 mm. Corolla tube infundibuliform, 1.2–2.2 × 1.5–2.0 mm, glabrous outside, with ring of white hairs inside; lobes 5, triangular, glabrous outside and inside. Anthers 5, reflexed. Style 2–6 mm, exceeding corolla tube, stigmatic-knob longer than wide, 0.4 × 0.2 mm, bifid, revealing a cleft at the apex. Ovary bilocular, 1–ovule per locule. Fruits ovoid to didymous, distinctly broader than long, 5 × 9–10 mm, green when young, puberulent, calyx persistent; pedicel 2.0– 3.2 cm, puberulent. Seeds 2, obliquely ovoid, ventrally flattened, 3–6 × 3 mm, apical crest very shallow to nearly inconspicuous, pyrene cartilaginous.

Distribution:—Luzon Island: Camarines Sur and Quezon

Habitat: —In limestone forest; 100–638 m altitude.

Phenology:— Flowering from March to December, and fruiting from December to March

Etymology:— The specific epithet was based on the puberulent inflorescence, fruit stalk and fruit of our material.

Additional specimens examined (paratypes):— PHILIPPINES. Luzon, Quezon Province: Alabat Island, Municipality of Alabat , Barangay Bacong , Mount Camagon , 14°09’N, 122°02’E, 130 masl, 21 March 1996, F . Gaerlan & E . Romero 23592 ( L!, PNH!). Polillo Island, Municipality of Burdeos , Barangay Amot , Sitio Igad , Burdeos Watershed Area , 14°50.80’N, 121°58.10’E, 2 May 1995, Romero, Garcia , & Majaducon 15396 ( L!, PNH!) .

Discussion:— The long stipular apex of P. puberula approximates that in Indonesian P. fasciculata (Blume) A.P. Davis (2008: 120) , nevertheless, several vegetative and floral characters distinguishes the former with the latter. Also, P. puberula resembles the Philippine endemic P. amplifolia (Merr.) A.P. Davis (2008: 120) in having a strictly elliptic leaf blade, cuneate leaf base and a prominent whitish midrib and lateral nerves. Table 1 shows the major differences that separate P. amplifolia from P. puberula . Furthermore, P. puberula is easily distinguishable from the other currently recognized Malesian Psydrax by its puberulent compound umbellate inflorescences with 14–25 flowers as well as a puberulent fruit stalk and fruit.

Conservation Status:—Examination of several undetermined herbarium specimens of Philippine and Malesian Vanguerieae from L and PNH revealed that there were no other previous collections of P. puberula other than the sheets examined in this study. In addition, recent botanical exploration of key forested areas in the Philippines failed to discover any plants that match our material. Psydrax puberula is restricted to forested regions of Camarines Sur and the nearby province of Quezon. Due to the severe fragmented distribution of our materials, being known only from the aforementioned three locations, P. puberula is a critically endangered species (CR B1a) based on the categories of the IUCN (2001). Hopefully this call attention to the urgent need to promote the conservation of this species, as well as the protection of the forested areas and their sustainable development.

Figures

FIGURE 1. Psydrax puberula Arriola and Alejandro, sp. nov. (from the holotype). A. Flowering and fruiting branch. B. Stipule. C. Ovary in longitudinal section with style and stigmatic knob. D. Open corolla. E. Infructescence. F. Fruit. G. Pyrene (2 views). Drawn by A.H. Arriola.