Kibara renneriae Takeuchi, 2012

Takeuchi, Wayne, 2012, Additions to the flora of the southern mountains of Papua New Guinea: Begonia chambersiae sp. nov. (Begoniaceae), Kibara renneriae sp. nov. (Monimiaceae), and distributional records of four rarely seen taxa, Phytotaxa 52 (1), pp. 43-53 : 47-48

Kibara renneriae Takeuchi , sp. nov. ( Fig. 4 )

Haec species Kibarae archboldianae affinis sed a qua ramulis teretibus (nec nodos incrassato-clavatis intus formicas hospitantibus), floribus femineis pedicellis nec carinatibus, drupis ovoideis (nec oblongo-ellipsoideis) ca. 18 × 15 mm differt.

Type: — PAPUA NEW GUINEA. Gulf Province: Lakekamu, near streambed of the Eloa River , upstream of the expedition base camp (Ivimka), alluvial forest, 7°44'S, 146°29.5'E, 105 m, 2 November 1996, Takeuchi & Kulang 11533 (holotype LAE!; isotypes A!, CANB!, K!, L!, UPNG!) .

Shrubs or small trees, 4–5 m tall. Branchlets terete (or apically compressed), 2.5–4 mm diameter, straight; surfaces laxly puberulent when immature, glabrescent, lineate (or smooth), yellowish-green to straw, without lenticels; internodes 4–14 cm long. Leaves opposite, equal, exstipulate; petioles 10–17 × 1–3 mm, channelled on upper side, longitudinally rugulose, glabrescent; leaf-blades chartaceous-papery, elliptic-oblong, 15.8–32 × 6.5–12.5 cm, base cuneate (or obtuse), margin entire (or denticulate), obscurely revolute, apex 1–2.2 cm acuminate; surfaces usually dull, glabrous or nearly so, adaxially olivaceous, abaxially tawny; venation brochidodromous, midrib adaxially flat to prominulous, abaxially prominent, secondary veins 6–12 per side, (0.5–) 1.5–5 cm apart, at the lamina center straight-diverging 60–75° from the midrib, supramedially arcuate, closing by abruptly looping nerves (2–)4–8(–10) mm from margins, anastomosing beyond the loops, with or without a second inframarginal set of commissural nerves parallel to the first, partial intersecondary veins usually present between the main laterals; reticulum conspicuous, irregular, finely areolate, nervules distinctly raised on both sides. Inflorescence axillary, monochasial or a racemiform dichasium, 2–4 × 2–3 cm, 1–4 together, strigulose; bracts inserted at the peduncle base and the nodes above, scalelike, ovate-deltate, 0.5–1 × 0.3–0.8 mm, persisting at anthesis, spreading, densely adpressed-hairy. Male flowers not seen. Female flower s (1–)3–6 per inflorescence; pedicel (6–)10–18 × 0.3–0.8 mm, widest at the top, filiform, not articulate; receptacle ellipsoid-obovoid, 3–3.5 × 2.3–2.5 mm at anthesis, 4.5–5 × 3.5–4.5 mm when abscissing, splitting near the middle, internal surfaces densely hirtellous; bracteoles 0–2, rotund, 0.1–0.2 × 0.3–0.7 mm, inserted within 1 mm of the ostiole; tepals 4 in 2 decussate pairs, obtuse, imbricate, medially swollen-glanduliferous, outermost tepals the largest, 0.3–0.5 × 0.5–1 mm; carpels 15–22, conoid-columnar, 1–1.3 × 0.2–0.4 mm, sessile, hirtellous; styles absent; stigmas rounded or acute, connivent, their apices occluding the orifice below the tepals. Infructescence of single receptacles from foliate axils; pedicels vasiform, 9–11 × 1–3 mm, round in cross-section (not carinate), dull orange-brown; receptacle discoid or globular, 5.5–7.5 mm across, accrescent; fruiting monocarps ovoid, ca. 18 × 15 mm, crustaceous, black, seated on ca. 1.5 × 2.5 mm cylindriform knobs.

Etymology: — Kibara renneriae is named after systematist Susanne S. Renner (Ludwig Maximilian University of Munich), a specialist in Melastomataceae and Monimiaceae .

Field characters: —Outer bark brown, wood light brown; branchlets shining green, often covered with a sooty mold, not ant-inhabited; leaves papyraceous, ± bullate, adaxially very dark green, abaxially yellowgreen (glaucescent when young); flowers dull yellow; fruiting monocarps purple-black.

Distribution: —Known from two lowland localities in the Gulf Province of PNG ( Fig. 3 : B–C).

Habitat and ecology: —Perhumid alluvial forest, 105–250 m elevation.

Phenology: —Flowering in November; fruiting in August.

Additional specimen examined: — PAPUA NEW GUINEA. Gulf District: Kikori Subdistrict, Purari River, Wabo Dam site, small gully, 7°00'S, 145°10'E, 250 m, 18 August 1975, Conn, Pattison, Sands & Wood LAE 66299 ( L, LAE!) .

The staminate inflorescence of Kibara renneriae is unknown, but the generic assignment is clear from the vegetative and pistillate characters enumerated in Philipson (1984: 482). The most significant of these applies to the pedicels, which in Kibara Endlicher (1837: 314) are distally expanded and not articulated at the receptacle. In the genus most likely to be confused with Kibara [viz., Steganthera Perkins (1898: 564) ] the pedicels are jointed at the top and not dilated. Although Kibara is also similar to Wilkiea Mueller (1858: 64) , the new species (having a sessile stigma) cannot be assigned to that genus because Wilkiea has a distinctly elongate style ( Philipson 1985: 390, 1986: 282–283). Even if future adjustments are imposed within the Mollinedioideae , Kibara is still the oldest name within the Kairoa-Kibara-Wilkiea clade. Under any likely scenario, the proposed binomial should be immune from nomenclatural disturbance.

Kibara renneriae was formerly assigned to K. archboldiana Smith (1941: 240) but this interpretation is no longer plausible (see discussion of K. archboldiana , next section). The two species are easily separated by the characters specified in the preceding diagnosis.

Figures

FIGURE 3. Island of New Guinea. Collection localities. A, Muller Range, type locality for Begonia chambersiae; B, Lakekamu, type locality for Kibara renneriae; C, Wabo; D, Tualapa; E, Juha North; F, Lordberg; G, Mt. Bosavi; H, Dieni; I, Kiunga; J, Mt. Amdutakin. Overlay (shaded area) shows distribution of the southern karst formations. A–E from the author's recent collections; F–J from historical localities of earlier collectors.

FIGURE 4. Kibara renneriae. A, sterile branchlets, nodes not inflated (compare with Fig. 6); B, inflorescence. A–B from Takeuchi& Kulang 11533.