Vaccinium jubatum M.N.Tamayo & P.W.Fritsch, 2022

Tamayo, Maverick N. & Fritsch, Peter W., 2022, Two new endemic species of blueberry (Vaccinium L., Ericaceae) from Luzon and Mindanao islands, Philippines, Phytotaxa 564 (2), pp. 139-148 : 143-145

Vaccinium jubatum M.N.Tamayo & P.W.Fritsch , sp. nov. ( Figs. 3–4 ).

Type: — PHILIPPINES. Mindanao Island, Bukidnon Province, Municipality of Impasug-ong, Sitio Intavas , Mt. Kitanglad , 18 July 1991, PPI [Philippine Plant Inventory] 3256 (holotype BRIT BRIT26945 !, isotype L L3786394 !) .

Paratypes: — PHILIPPINES. Mindanao Island, Bukidnon Province, Mt. Kitanglad (southern slope), 2200 m elevation, 16 March 1949, Sulit 3390 ( A 00016194 !, L L0008222 !) .

Diagnosis:— Vaccinium jubatum resembles V. sylvaticum Elmer (1911: 1095) but differs by having dentate leaf margins (vs. entire), shorter inflorescences (2–5 cm vs. 5–8 cm), shorter pedicels (3.0–5.0 mm vs. ca. 7.5 mm), a glabrous calyx (vs. puberulent), and shorter filaments (2.5–2.8 mm vs. ca. 3.5 mm).

Description:—Habit shrub or vine, epiphytic, evergreen, multi-branched. Branchlets brown, terete, 2–5 mm wide, glabrous, lenticellate; perennating buds broadly triangular, 1.5–2.0 mm long; bud scales overlapping, margins ciliolate. Leaves persistent on older branchlets, spirally and evenly arranged, glossy and dark green adaxially, light green abaxially, slightly overlapping, internodes 5–10 mm long; petiole dark brown, in cross-section rounded abaxially and flattened adaxially, 3.0–7.0 × 1.5–3.0 mm, glabrous; leaf blade elliptic, with larger blades on each branchlet 4.0–7.5 × 1.2–2.0 cm, coriaceous, both surfaces glabrous, brown, abaxially with scattered minute punctae; midvein strongly raised abaxially, slightly raised adaxially, secondary veins 3 or 4 on each side of midvein with first pair arising from base and remainder along midvein, arc-ascending, abaxially and adaxially raised, tertiary veins faintly evident or obscure, base cuneate, margin dentate, non-revolute, teeth tipped by a prominent gland, 8 to 12 per side, scattered along length of margin but more concentrated toward apex, 0.5–0.8 mm wide, apex acuminate. Inflorescences pseudo-terminal or terminal, racemose, developing beyond confines of perennating bud, 1 per axil, 2–5 cm long at anthesis, densely 10- to 14-flowered; peduncle and rachis dark brown, slightly ridged, terete, glabrous; bracts early caducous. Pedicel nodding, 3–5 × 0.4–0.5 mm at anthesis, terete, spreading, glabrous, occasionally with 1 or 2 globose glands near base; ebracteolate. Flowers articulated at junction with pedicel, 2.5–6.0 mm long. Hypanthium dark brown, 1.2–1.4 × 1.2–1.5 mm, glabrous; calyx limb 0.9–1.1 mm long, glabrous; calyx lobes 5 or 6, crescent-shaped, 0.7–0.8 mm long, glabrous, margin entire, ciliolate, rounded, with a sessile terminal gland. Corolla ampullaceous, white in upper 1/3 portion, pink at base, 4–5 × 1.3–2.2 mm, both sides glabrous; corolla lobes 5 or 6, 0.5–0.8 × 0.4–0.5 mm, apex obtuse to rounded. Stamens 8–10, monomorphic, 3.5–4.0 mm long; filaments light brown, straight, bulged at base, 2.5–2.8 mm long, white-lanate especially toward base, trichomes 0.2–0.4 mm long; anthers 1.0– 1.2 mm long, cells 0.7–0.8 mm long, minutely echinulate, tubules parallel, broadly cylindrical, opening by oblique ventrally oriented apical pores, 0.3–0.4 mm long, pore apex rounded or truncate, spurs absent. Ovary 5- or 6-locular but appearing pseudo-10- to 12- locular with false partitions extending ca. 0.5 mm from inner wall; ovules in two columns per locule. Disk annular, slightly bulky, ca. 0.7 mm × ca. 1.5 mm, glabrous, margin obscurely ridged. Style brown, not exserted from corolla, 4–6 mm long, glabrous. Fruit dark brown, globose, smooth, non-ridged, 4–5 × 4–5 mm, glabrous, slightly recurved; fruiting pedicels ca. 5 mm long.

Distribution and Habitat: —This new species is endemic to Mindanao Island, Southern Philippines. It occurs on the northeastern and southern slopes of Mt. Kitanglad Range. Paratypes of V. jubatum were collected near the vicinity of the summit at 2200 m elevation.

Etymology: —The specific epithet “ jubatum ” is derived from the Latin word “jubatus” meaning “crested.” This is in reference to the dentate leaf margin of the new species that is tipped by a prominent gland.

Phenology: —Flowering in March and July.

Proposed Conservation Status: — Vaccinium jubatum is currently only known from its type locality. We know of no other collections of this species. Although Mt. Kitanglad Range is a protected area, the lack of population data precludes assessment with IUCN guidelines. Thus, we recommend a Data Deficient (DD) status for this species ( IUCN Standards and Petitions Committee 2022).

Discussion: — Vaccinium jubatum is a member of Vaccinium sect. Bracteata Nakai in Nakai and Koidzumi (1927: 234) sensu Sleumer (1966 –1967) as per its multi-flowered racemose inflorescences, (minute) caducous bracts, absence of a membranaceous wing at the sinuses of the corolla, and anthers that open by short terminal pores or introrse slits ( Sleumer 1966 –1967; Co et al. 2002; Salares et al. 2018).

In the artificial key to Philippine Vaccinium ( Copeland 1930) and the key to the Malesian Vaccinium ( Sleumer 1966 –1967), V. jubatum keys to V. sylvaticum , a species endemic to Mindanao Island. It is distinguished from this species by having longer petioles (3–7 mm vs. ca. 5 mm), shorter corollas (4–5 mm vs. ca. 8 mm), shorter anthers (1.0– 1.2 mm vs. ca. 1.5 mm), and a shorter style (4–6 mm vs. ca. 8 mm) ( Elmer 1911; Sleumer 1966 –1967). In the key to Bornean Vaccinium ( Argent 2019) , V. jubatum keys to V. phillyreoides Sleumer (1940: 163) . However, the new species is distinct from V. phillyreoides by having glabrous branchlets (vs. puberulent), larger leaf blades (4.0–7.5 × 1.2–2.0 cm vs. 2.2–3.0 × 0.5–1.0 cm) with dentate leaf margins (vs. entire), glabrous inflorescences (vs. pubescent), shorter pedicels (3–5 mm vs. 5–7 mm), shorter corollas (4–5 mm vs. 8–9 mm), shorter stamens (3.5–4.0 mm vs. 6.0–7.0 mm), and a glabrous disk (vs. densely pubescent). Moreover, the dentate leaf margins with large and raised marginal glands are unique to V. jubatum among the species of Philippine Vaccinium .

The specimens Sulit 3390 (A 00016194!; L L0008222!) were annotated as Vaccinium sulitii P.F.Stevens , a name that apparently was never published. These specimens clearly belong to V. jubatum as exhibited by the dentate leaf blade margins. The reason that this name was not published might be because the specimens are merely in flower bud, thus making it difficult to dissect and examine the flower characters within the corolla.

Figures

FIGURE 3. Vaccinium jubatum. A. Flowering branch. B. Adaxial view of part of a leaf showing the marginal glands. C. Flower. D. Flower (corolla removed) exposing the style and disk. E. Lateral view of stamen. F. Ventral view of stamen. Illustration by Maverick N. Tamayo.

FIGURE 4. Holotype of Vaccinium jubatum M.N.Tamayo & P.W.Fritsch (BRIT BRIT26945). Image courtesy of the Botanical Research Institute of Texas.