Hypericum perryongii Galindon, 2021

Galindon, John Michael M., Penneys, Darin S., Lagunday, Noel E., Tandang, Danilo N., Coritico, Fulgent P., Amoroso, Victor B. & Fritsch, Peter W., 2021, Hypericum perryongii (Hypericaceae), a new species from Philippines, Phytotaxa 478 (1), pp. 61-66 : 62-65

Hypericum perryongii Galindon , sp. nov. ( Figures 1 & 2 )

Diagnosis: — Hypericum perryongii closely resembles H. geminiflorum based on leaf morphology, completely united styles of 5, and bright yellow petals and anthers. Hypericum perryongii , however, is distinguished from H. geminiflorum by its always 1-flowered and terminal inflorescences (vs. 2- to 3-flowered and axillary), larger flower diameter (40–45 mm vs. 20–30 mm), larger sepals (6–8 × 3–4 mm vs. 1.5–2.5 × 1–1.5 mm), larger petals (20–22 × 15–17 mm vs. 9–15 × 5–7 mm), higher number of stamens per fascicle (25–30 vs. 6–11), longer styles (13–16 mm vs. 4–7 mm), and ovoid capsules (vs. narrowly cylindric). It is also similar to the Taiwanese species H. formosanum Maximowicz (1881: 428) but H. formosanum has terminal inflorescences that are 1–3-flowered and 1–2-flowered on subsidiary branches (vs. strictly terminal and 1-flowered in H. perryongii ) and sessile and not glaucous leaves (vs. subsessile and abaxially glaucous).

Type: — PHILIPPINES. Mindanao Island: Davao Oriental Province, San Isidro Municipality, La Union Barangay , Mount Hamiguitan Range Wildlife Sanctuary , 1563 m, 6.73728°N, 126.18364°E, Tropical Upper Montane Rain Forest , mossy forest going to peak, 18 June 2019, Plants and Lichens of the Southern Philippines Survey 1320 (holotype PNH!, isotypes BRIT!, CMUH!) .

Description: — Erect shrub, 0.5–1.5 m, stems and branches reddish brown, dark red at tip of young twigs, terete, nodes swollen in mature stems. Leaves subsessile, decussate, broadly elliptic-lanceolate, 14–39 × 4–21 mm, thinly coriaceous, glabrous, abaxially glaucous, adaxially dark green, base broadly cuneate to obtuse, margin entire and slightly revolute, apex subacute to obtuse, usually apiculate; midvein and lateral veins keeled abaxially, more or less flat adaxially, with 6–8 lateral veins on each side of midvein, reticulations not persistent, or scarcely branched, either first or second basal vein uniting to the other succeeding lateral veins to form strong intramarginal vein towards apex; laminar gland dots pale, dense. Inflorescence always terminal, 1-flowered; pedicel yellowish green, terete, clavate, 4–7 mm long. Flowers slightly concave, 40–45 mm in diameter; buds narrowly ovoid. Sepals free or slightly connate at base, ascending in buds and fruits, pale green, ovate to oblong-lanceolate, 6–8 × 3–4 mm, surface glands pale, linear, margin entire. Petals bright yellow, broadly obovate, 20–22 × 15–17 mm, entire to subundulate, surface glands all pale, linear, apiculus absent. Stamen fascicles 5, 7– 11 mm long, each with 25–30 stamens; anthers bright yellow, glands not observed. Ovary ovoid, 3–5 × 2–3 mm; styles 5, completely united, 13–16 mm long, more than twice as long as the ovary; stigmas completely united, forming rounded mass; placentae 5. Capsule 9–12 × 4–7 mm, septa 5, yellowish green when young turning purplish red when mature, ovoid, dehiscent when mature. Seeds brown, narrowly cylindric, usually falcate, 0.5–0.7 × 0.15 mm, with narrow wing-like apical expansions.

Additional specimen examined: — PHILIPPINES. Mindanao Island: Davao Oriental Province, San Isidro Municipality, La Union Barangay , Mount Hamiguitan Range Wildlife Sanctuary , 1563 m, 6°44′14.0″N, 126°11′1.7″E, forest on ultramafic soil, 13 August 2019, V. B . Amoroso 18826 ( BRIT!, CMUH!, PNH!) .

Distribution and habitat: — This species is endemic to the Philippines, Mindanao Island, Davao Oriental Province, San Isidro Municipality, in the MHRWS. It was encountered on a narrow and exposed ridge near the mountain summit with an ultramafic substrate at 1563 m a.s.l.

Phenology: — Flowering during June, and possibly until late July; fruiting in August.

Etymology: — The species is named in honor of Dr. Perry S. Ong (1960–2019), renowned academician, scientist and conservation biologist from the University of the Philippines-Diliman. Throughout his career, Dr. Ong championed the protection and conservation of Philippines biodiversity through science-based policies and the participation of local communities.

Notes: — This species belongs to Hypericum section Takasagoya as characterized by its completely united styles ( Robson 2012). Robson (2012) listed five species under this section, namely; H. formosanum , H. nakamurae ( Masamune 1940: 410) N. Robson (1972 publ. 1973: 253) (≡ H. formosanum var. nakamurae (Masam.) S.S. Ying (1995: 185)) , H. senkakuinsulare Hatusima (1973: 2) , H. geminiflorum with a derivative subspecies H. geminiflorum subsp. simplicistylum ( Hayata 1911: 41) N. Robson (1972 publ. 1973: 254) and H. subalatum Hayata (1911: 41) . These species are only found in Taiwan, except for H. geminiflorum which can also be found in Luzon Island, Philippines and H. senkakuinsulare which is confined to the Ryukyu Islands, Japan.

The new species resembles both H. geminiflorum and H. formosanum but is distinct in its always 1-flowered and terminal inflorescence. It can be placed with the long-sepalled group of H. formosanum , H. nakamurae and H. senkakuinsulare . However, the abaxially glaucous leaves distinguishes H. perryongii from all other species in section Takasagoya .

Based on Nickrent et al. (2006 onwards), Leonard Co documented a species of Hypericum (plant1; DOL nos. 31740 and 31741) in Bukidnon, Mindanao in 2007. This may be the first record of Hypericum in the island of Mindanao. On close inspection of the photos of the plant, it is quite distinct from H. perryongii and warrants a specimen collection for comparison with the known Hypericum species.

Conservation status: — Hypericum perryongii is only known from a single individual at the type locality, within the 68.34 km 2 MHRWS. We estimate that there are <50 individuals of this species in the area because we were unable to observe additional populations especially at elevations below the summit. Thus, the species may likely warrant the category of Critically Endangered (CR) based on the IUCN Standards and Petitions Subcommittee (2019). However, because our current data are so uncertain and there is still a need to gather more information about its current status and threats, we recommend the category Data Deficient (DD).

Figures

FIGURE 1. Hypericum perryongii Galindon sp. nov. A. Flower. B. Fruit. C. Abaxial leaf surface of a dried leaf showing dense glandular dots. D. Seeds. E. Portion of the narrow summit of Mount Hamiguitan where the species was collected. F. Habit. Scale bars: 1.0 cm (A, B, C, F); 0.5 mm (D). Photos: A–E by J.M.M. Galindon; F by D.N. Tandang. (A–E from Plants and Lichens of the Southern Philippines Survey 1320; F from V.B. Amoroso 18826.)

FIGURE 2. Hypericum perryongii Galindon sp. nov. A. Flowering branchlet. B. Leaf, abaxial view. C. Sepal. D. Petal. E. Fruit. F. Seed. A, D by Samuel Guarino; B, C, E, F by J.M.M. Galindon. (All from Plants and Lichens of the Southern Philippines Survey 1320.)