Monimiaceae

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 : 49-50

Monimiaceae

Kibara archboldiana Smith (1941: 240) . Type :— PAPUA NEW GUINEA. Central Division : Dieni ( Fig. 3 : H), Ononge Road, rain forest, 500 m, 2 May 1933, Brass 3938 (holotype NY; isotype A!). Figs. 6–7 .

Additional specimen examined: — PAPUA NEW GUINEA. Western Province: Strickland drainage, Juha North ( Fig. 3 : E), perhumid hill forest, 5°48.473'S, 142°18.672'E, 240 m, 31 March 2008, Takeuchi, Gambia & Jisaka 23620 ( A!, LAE!, and 2 undistributed duplicates!) .

The Strickland collection keys directly to Kibara latifolia Philipson (1985: 396) , but obviously does not belong there. The actual identity is with K. archboldiana . Because of the vegetative variation in newly discovered populations, the preceding taxa cannot be reliably separated at Philipson's (1985: 392, 1986: 289) couplet 7. The following substitution is suggested to the existing key in order to correct the discrepancy:

7a. Leaf apices obtuse; ripe monocarps ovoid, 10–12 × 6–8 mm ( Moluccas, Halmahera; Indonesia) ....... Kibara latifolia 7b. Leaf apices acuminate-caudate, acumen/cauda (9–)15–25 × 1–2.5(–5) mm; ripe monocarps ellipsoid-oblongoid, 16–

23 × 8–10 mm (Western and Central Provinces; Papua New Guinea) ......................................... Kibara archboldiana

Kibara archboldiana is one of four myrmecophytic congeners; the others include K. carrii Philipson (1985: 405) , K. ferox Philipson (1985: 395) and K. latifolia . Whether by coincidence or not, all Kibara with ant associations are also macrophyllous plants whose leaves are among the largest in the genus.

A non-myrmecophytic Kibara (with stems lacking swollen nodes) was explicitly assigned to K. archboldiana by Philipson (1985: 396) despite the presence of several discordant features. Previously exemplified only by LAE 66299 (fruiting), this morphotype was recently collected in flower during the CI Lakekamu Expedition and was tentatively identified as K. archboldiana based on Philipson's discussion of that species ( Takeuchi & Kulang 1998: 120).

With the complete material of K. archboldiana now in hand, it has become clear that the nonmyrmecophytic form is actually a distinct species. The pistillate inflorescence in K. archboldiana sens. str. is very unusual—the receptacle is conspicuously compressed and the dilated part of the subtending pedicel has a very prominent median keel. These characters persist into the post-anthetic stage and disappear only with expansion of the receptacle during the process of fruit maturation.

In the two specimens referable to Philipson's non-myrmecophytic ' archboldiana ', the newly appreciated pistillate markers are missing. When combined with the absence of myrmecophytic structures and the different form of the achenes, there is no doubt that the Gulf Province Kibara cannot be K. archboldiana . This previously misidentified species has been described in the preceding section as K. renneriae , and is probably sister to K. archboldiana .

An auxiliary description of the pistillate inflorescence for K. archboldiana is provided below. Only the male flowers were known to Philipson (1985, 1986).

Female inflorescence axillary or supra-axillary, mostly racemose, 9–23 × 8–12 mm, erect, fuliginous, densely adpressed-puberulent on all exterior surfaces; peduncle 5–8.5(–16) × 0.5–1 mm; peduncular bracts paired, opposed, inserted basally and at the top, acute, ca. 1 mm long, caducous. Female flowers (1–)2–5; pedicels conspicuously compressed, prominently marked by a median keel on both sides, distally expanded, subturbinate, 4.5–6 × 1–2 mm at anthesis, 8–11 × 2–2.5 mm immediately after receptacle abscission, not articulated; bracteoles 2, scalelike, 0.3–0.5 mm long, caducous; receptacle cupuliform, (1–)3–4 × 1.5–2.5 mm, acutely pointed at the orifice, circumscissile, angulate, internally hirtellous; tepals 6 in 3 decussate pairs, minutely ovate, not discernably glanduliferous (in pre-anthetic flower); carpels 9–14, ellipsoid-oblongoid, ca. 0.9 × 0.2 mm, sessile, hirtellous; no style; stigma discoid-pulviniform.

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 6. Kibara archboldiana. A, branchlets, apical nodes claviform-inflated; B, apical nodes on the A isotype for K. archboldiana; C, compressed receptacles and pedicels conspicuously furnished with a median keel. A and C from Takeuchi, Gambia & Jisaka 23620; B from Brass 3938.

FIGURE 7. Kibara archboldiana. A, early infructescence; B, submature infructescence; C, branchlet with ant-entry hole (ants faintly visible on the monocarps). A–C from Takeuchi, Gambia & Jisaka 23620.