Friesodielsia yelaensis Ezedin, 2024

4. Friesodielsia yelaensis Ezedin View in CoL , sp. nov. — Fig. 5 View Fig ; Map 1 View Map 1

Differs from F. subaequalis in having caudate leaf apices, shorter pedicels, larger foliaceous medial bracts that are equal to or larger than the sepals, longer more prominent sepals. — Type: Brass 28329 (holo A [ A00871712 ];iso BO [1372564], L [ L.1765025] photo, LAE [29454],US [ US 03900190] photo), Papua New Guinea, Milne Bay, Rossel Island, Abaleti , 50 m, 5 Oct. 1956 (fl) .

Etymology. After the indigenous name of Rossel Island (Yela).

Woody climbers. Twigs slender, terete, twining, when young densely rusty brown pubescent, when older longitudinally striate and black. Indument of simple hairs, dark brownish orange, covering twigs, petioles, and primary vein. Leaves oblong to obovate, (8.5–)10–14(–17.6) by 3–5(–6.8) cm, chartaceous, dark olivaceous to light brown above and dark olivaceous below in sicco, apex (acute to) acuminate to (strongly) caudate, base (sub)cordate, margins entire; petioles 6–11 by c. 2 mm, terete, adaxially flattened to weakly grooved, densely rusty pubescent when young then becoming glabrous, black; venation eucamptodromous to weakly brochidodromous, primary vein flat to weakly impressed above, prominent below, secondary veins 14–16(–18), ± flat above, weakly raised below, spaced 9 –20 mm apart, intersecondaries absent, tertiary veins prominent below, straight percurrent, closely spaced, c. 45° to the primary vein, quaternary veins irregular, forked to straight percurrent. Flowers solitary, internodal, supra-axillary and nearly leaf-opposed, appearing just below the leaf axils opposite the leaves, brown prior to anthesis; pedicels 0.3–1 by c. 0.1 cm, densely brown pubescent; bracts borne at c. 1/2 the distance from the base or appearing basal when flowers are subsessile, large, narrowly triangular, foliaceous and with distinct venation to the third order, equal to or larger than the sepals, 14–17 by 2–3 mm, pubescent on both sides, with hairs more dense on the primary vein and base; sepals 3, free, triangular, 10–14 by 3–4.5 mm, apex acuminate, pubescent on both sides, with hairs more dense on outer side and towards the base; outer petals 3, narrowly ovate-triangular, 50–65 by 5–7 mm, outer side (sparsely) hairy, inner side glabrous, with a prominent midrib; inner petals 3, narrowly ovate, c. 1/4 the length of the outer petals, c. 16 by 4–5 mm, glabrous, with a small tuft of hair at the apex; stamens 50–60, in 3–4 series, 1.5–2 mm long, connective apex truncate, pentagonal, irregular, curved away from thecae towards the stigmatic center, without prominent prolongation; carpels many, in 2–3 series, 3–3.5 mm long, stigmas 1–1.5 mm long, apex hairy, broad, curving outwards, partially covering the adjacent stamen series, ovaries c. 2 mm long, with appressed long hairs, ovules 1 per ovary. Fruits unknown.

Distribution — Papua New Guinea (Rossel Island). Only known from the type collection.

Habitat & Ecology — Found in lowland rainforests at 50 m a.s.l. Flowering: October. Pollinators and dispersers unknown.

Conservation status — Data Deficient (DD). Thus far only known from the type collection from Rossel Island. Threats to the species are unknown, along with its true extent of occurrence. However, assuming the species is endemic to the island and given the island’s small size of 292.5 km 2, likely with an even smaller area of suitable habitat in non-degraded lowland forest, it would likely qualify as either endangered or critically endangered ( IUCN 2022). Whether or not this species occurs at higher elevations is also not yet known, although this may be inconsequential assuming its endemicity to the island. Unfortunately, further field assessment would be needed to confirm its extent of occurrence on the island and whether or not populations are present on any adjacent islands of the Louisiade Archipelago (i.e., Sudest, Misima).

Notes — 1. Friesodielsia yelaensis is unique in the genus in several respects. First, it represents both the southernmost and easternmost occurring species of the genus at 11° south and 154° east. Its morphology is equally striking with its subsessile flowers and large triangular bracts and sepals, both of which are foliaceous. While large, foliaceous bracts and sepals are found in some other species such as the Indochinese F. affinis (Hook.f. & Thomson) D.Das and the Peninsular Malaysian F. calycina , it is thus far unique for eastern Malesia. The combination of both floral and leaf traits easily distinguish this species from others in the region.

2. Being recorded from Rossel Island is also unique in itself. The island, which is the easternmost of the Louisiade Archipelago, is known to harbour an unusually high level of endemism for its small size of just under 300 km 2. There are a total of 38 endemic species recorded from the island, representing a wide array of families and even an endemic genus, Rosselia Forman ( Burseraceae ) ( Johns et al. 2009). Given this, it is likely that there are additional endemic taxa from the island that await description.