Saurauia zamboangensis Merr. (1925: 471)

Mazo, Kean Roe F. & Aribal, Lowell G., 2025, Rediscoveries, lectotypifications and new species record of the genus Saurauia (Actinidiaceae) from southwestern Philippines, Phytotaxa 704 (1), pp. 69-78 : 73-75

2. Saurauia zamboangensis Merr. (1925: 471) ; Fig. 3 A–N

Type:— Philippines, Mindanao, Zamboanga, Mount Tubuan, 30 October 1919, elevation 500 m, BS 36607 Ramos & Edaño (lectotype (designated here): A 00098377!, isolectotype: US 00110167!).

Description:—Shrub to small tree, up to 5 m tall, 10 cm in diameter at breast height, outer bark greenish brown, lenticels sparse. Branchlets terete, green. Distal portions of the twigs with dense reddish (brownish when old) scales; longer scales appressed to ascending, narrowly lanceolate to triangular, 2.5–6.0 mm long; shorter scales acicular to linear, up to 2 mm. Leaves alternate, simple, chartaceous; petiole terete, pale green, 1.3–2.6 cm long, 4–5 mm in diameter, indumentum similar to that of distal twigs; young leaves green; blade lanceolate, 24–34 × 4.0– 9.5 cm, adaxially olivaceous, glabrous except the midrib with sparse acicular scales; abaxially pale green, with appressed acicular hairs (0.5–2.0 mm long), denser in the midrib, secondary veins and reticulations; secondary veins 12–14 pairs, prominent on the lower surface, 22–35 mm apart along the midrib, reticulately veined, arching and fading towards the leaf margin, base acute, margin spinose (hairs up to 1.7 mm long), apex sub-caudate to acuminate. Inflorescences cauliflorous, borne on tubercle, fascicle cymose, many-branched, 3–7 cm long; flowers rotate, 5–12 per peduncle, 1.5–2.0 cm in diameter, odorless; peduncle brownish-red, 5–11 mm long, with dense appressed, reddish, acicular hairs (1.5 mm long); bracts 2, red, triangular, 1.4–1.5 × 0.5–0.7 mm, with appressed reddish, acicular hairs (0.7–1.3 mm long); bracteoles 2, red, triangular, 1.5–1.6 × 0.5–0.7 mm, indumentum similar to the bracts; pedicels brownish-red, 9–22 mm long, indumentum similar to that of peduncles. Sepals 5, white, pinkish-red in fruits; outer sepals 2, white, oblong-ovate, 6.0–7.5 × 2.5–4.3 mm (excluding setae), adaxial surface glabrous, abaxial surface with red, appressed, linear to lanceolate scales (up to 1.3 mm long), margin entire, apex acute to obtuse; intermediate sepal present, partly covered with hairs similar to outer sepals and partly glabrous similar to inner sepals; inner sepals 2, white, oblong to ovate, 6.3–8 × 2.6–4.5 mm (excluding setae), adaxial surface glabrous, abaxial surface with indumentum similar to that of outer sepals but scale only present at the median base of the inner sepals, margin entire, apex bluntly acute-obtuse. Petals 5, white, oblong-elliptic, 7.5–9.0 × 4.5–6.0 mm, glabrous on both surfaces, apex unequally retuse, sinus 0.4–0.8 mm long. Stamens 13–18, yellow, in two series, adnate to the base of the corolla; filaments yellow, 1.0– 1.3 mm long, glabrous; anthers 3.0– 3.2 mm long × 0.3–0.4 mm wide, oblong, dorsifixed, longitudinally dehiscent, apex divided into 2 lobes, lobes 0.1–0.2 mm long. Ovary white, ovoid, 2.0–2.2 × 3.0– 3.5 mm, glabrous; locules 3, placentation axile, ovules numerous. Styles 3, white (reddish in fruit), proximal 25–28% fused, filiform, 3.5–4.0 mm long, upper arms free; stigma capitate, minutely corniculate. Fruits baccate, translucent white, globose to subglobose, 8.5–10.0 × 7.5–9.5 mm (styles excluded), glabrous, styles persistent. Seeds numerous, brown to black, irregular triangular to oblong, 0.3–0.5 × 0.1–0.4 mm, embedded in mucilaginous matrix.

Distribution and Ecology:— Endemic to the Philippines. In the Barangay Talisayan, Zamboanga City, this species is found in a primary forest at 500–1000 m elevation. In Barangay Tinuyop, Leon B. Postigo, populations were seen thriving in a secondary evergreen lowland tropical forest at 200–350 m elevation. Saurauia zamboangensis has been observed flowering and fruiting from February to August.

Local name and Uses: —Locals in Zamboanga del Norte call Saurauia zamboangensis as himag-pula whereas it is known as sasaua for the Subanen, an indigenous group in the Zamboanga peninsula ( Merrill, 1925). Its fruits are consumed as a forest snack.

Provisional IUCN conservation assessment:— The area of occupancy (AOO) of Saurauia zamboangensis is estimated to be less than 500 km 2 (296.00 km 2; Bachman et al. 2011). Additionally, only 50–100 and 30–50 mature individuals were observed in Barangay Talisayan, Zamboanga City, and Barangay Tinuyop, Leon B. Postigo, Zamboanga del Norte, respectively. The habitats of both populations face the threats of infrastructure development for ecotourism and water supply, agricultural expansion, and unregulated small-scale mining. We therefore categorized S. zamboangensis as Endangered (EN B2b(iii)) following IUCN red list categories and criteria ( IUCN, 2022).

Notes:— Saurauia zamboangensis is unique among all Philippine Saurauia species by its lanceolate, slender, subcaudate-acuminate leaves that are adaxially glabrous and conspicuously appressed setose on the midrib. In Barangay Tinuyop, S. zamboangensis occasionally grows sympatrically with S. denticulata .

Additional specimen examined:— PHILIPPINES. Mindanao, Zamboanga del Norte Province, Municipality of Leon B. Postigo , Barangay Tinuyop , 8°3’52.46”N, 122°55’44.66”E, elevation 316 m, 17 February 2021, K. R. F. Mazo 17 ( PNH258580 !; CMUH!)

Figures

FIGURE 3. Saurauia zamboangensis Merr.A. Leafy branchlet; B. Leaf (adaxial view); C. Leaf (abaxial view); D. Distal portion of twig; E. Portion of abaxial leaf surface showing the midrib; F. Leaf margin; G–H. Cauliflorous inflorescences; I. Flower; J. Sepals, ot (outer sepals), it (intermediate sepal), in (inner sepals); K. Petals; L. Pistil with corolla and 3 petals removed; M. Cross-section of the ovary; N. Infructescence. Photos by K.R. Mazo.