Gossia kuakuensis, N.Snow, 2010

Snow, Neil, 2020, A revision of New Caledonian Gossia N. Snow & Guymer (Myrtaceae), Adansonia 42 (7), pp. 131-177 : 160-161

Gossia kuakuensis (Baker f.) N. Snow ( Figs 14 ; 15D-H ; 16A-C )

Austrobaileya 8: 181 (2010). — Psidium kuakuense Baker f., Journal of the Linnaean Society, Botany 45: 318 (1921). — Typus: New Caledonia. Grande Terre, South Prov., Kuakué (= Kouakoué) , 13.V.1914, Compton 930 (holo-, BM [ BM000581652 ]). Psidium floribundum Vieill. ex Guillaumin, nomen nudum, Annales du Musée colonial de Mareille, sér. 2, 9: 150 (1911). — See discussion in Snow & Veldkamp (2010: 181) regarding this unpublished name.

Eugenia cataractarum Guillaumin, Bulletin de la Société botanique de France 85: 636 (1939). — Austromyrtus cataracarum (Guillaumin) Burret, Notizblatt des Botanischen Gartens und Museums zu Berlin-Dahlem 15: 503 (1941).

— Typus: New Caledonia. Grande Terre, South Prov ., Secus ripus torentium prope Touho, Vieillard 2171 (lecto-, P [ P00602576 ] designated here; isolecto-, G, GH[GH00071539], P[P00751830]).

SPECIMENS EXAMINED. — New Caledonia. North Prov., Näräjaa, Ponerihouen, 550 m, 26.III.2016, Fleurot 226 (P[P01168448]) ; Pente Sud du Mt. Kaala, 12. VI.1965, MacKee 12758 ( NOU [ NOU029641 ], P[P00462879, P00462880]) ; Pente Sud-Ouest du Mt. Kaala, 300-600 m, 10.IX.1967, MacKee 17490 ( NOU [ NOU029640 ], P[P02089978, P05094102) ; Massif de Tion-non , 800-900 m, 21.III.1968, MacKee 18516 (P[P02089982] ; Col d’Amieu-Ouambéa, 500-600 m, 31.III.1970, MacKee 21745 ( NOU [ NOU030905 ]) ; Bord des torrents, Wagape, Vieillard 2171bis ( BISH, P[P00462881, P00462882]) ; Bord des torrents à “Poinendu”, Vieillard 2218 (G[G00340965, G00340992, images seen], MEL n.v., P, 2 sheets) .

REPRESENTATIVE HERBARIUM SPECIMEN. — P02089978. ETYMOLOGY. — From the type locality.

DISTRIBUTION, HABITAT AND PHENOLOGY. — Scattered on Grande Terre ( Fig. 14 ); in maquis on ultramafics or edges of dense moist forests over sedimentary volcanics, 100-600 m (but more data needed; see remarks). Flowering March through June; fruiting confirmed only for September.

DESCRIPTION

Shrubs or trees

1- 6 m.

Branchlets

Terete to compressed (the older branchlets with dark, rectangular flakes); internodes> 5 mm.

Leaves

Coriaceous, 2 per node; petioles 1.5-4 mm (or leaves sessile), sometimes slightly sulcate; blades (3-)4.5-9.0 × 3.0-6.0 cm, elliptic to broadly elliptic, base rounded to cordate or clasping, surface flat to somewhat creased along midvein, margin flat to slightly irregular, apex obtuse, midnerve above flush to slightly sulcate at base, secondary veins flush above, oil glands of lower surface dense but indistinct.

Inflorescence

2.5-8.5 cm, a dichasium, raceme or panicle, terminal or axillary; pedicels (1.5-) 4-11 mm; extrafloral bracts leaflike.

Bracteoles

1.5-4.5 mm, linear to narrowly elliptic, glabrous to sparsely sericeous.

Hypanthium

Obconic, 2.3-2.6 × (2-)3.4-3.8(-4.2) mm wide, surface smooth, glabrous; ovary apex glabrous.

Calyx

Lobes 5, 1.5-3 mm, broadly rounded, ciliate but otherwise glabrous, green.

Petals

4-6 × 3-5 mm, white, sparsely ciliate on margins.

Filaments

2.5-4.5(-6) mm; anther sacs c. 0.5 mm. Style 3-5(-6.5) mm, glabrous to sparsely sericeous.

Fruits

5.5-10 × 5.5-10 mm, subglobular to globular, base rounded, green when young (mature color unconfirmed); seeds 1-4.

REMARKS

The bark of branchlets and main trunk typically breaks into dark rectangular flakes, and the branches reportedly can be pendant. Some leaves on the holotype are atypically clasping. The peduncles in the inflorescence are glabrous but can be prominently striate.

We tentatively here include Fleurot 226 ( Fig. 16A-C in Näräjaa, Ponérihouen), although its leaves are sessile and slightly clasping, whereas other specimens have short petioles, and its fruits have 4-merous calyx lobes. Study of herbarium vouchers (unavailable before submission) will help determine its proper placement.

Figures

FIG. 14. — Distribution maps of Gossia conspicua (Guillaumin ex Vieill.) N. Snow, comb. nov., G. katepahiensis N. Snow, sp. nov., and G. kuakuensis (Baker f.) N. Snow.

FIG. 15. — A-C, Gossia katepahiensis N. Snow, sp. nov.: A, branch with inflorescences; B, flowers in bud; C, detail of flower bud (in longitudinal section at right); D-H, Gossia kuakuensis (Baker f.) N. Snow: D, flowering branch; E, detail of simple cyme (note small leafy bracts at base); F, detail of flower (minus petals and stamens); G, young fruit and leaf;H, older branch with attached leaf showing dark,more or less rectangular cracking in epidermal layers; I, J, Gossia mandjeliaensis N. Snow, sp. nov.: I, flowering branch (detail of cracking outer epidermal layers (lower left) and abaxial oil glands (upper left)); J, flower from above (lacking petals and stamens) (left) and laterally (right). Vouchers: A-C, McPherson 5690 (WELTU – from 2 sheets); D-F, Compton 930 (BM); G, Vieillard 2171 (P); H, Vieillard 2218 (P); I-J, McPherson 2551 (P). Scale bars: A, D, 2 cm; B, E-G, 5 mm; C, J, 3 mm; I, 2 mm. Scale bar lacking: H, leaf c. 5 cm long.

FIG. 16. — A-C, Gossia kuakuensis (Baker f.) N. Snow vel aff.: A, inflorescences and leaves;B, leaves and branchlets with dark rectangular flaking bark; C, young fruits; D, Gossia pancheri. Vouchers: A-C, Fleurot 226 (NOU, P); photo ©Dominique Fleurot, with permission; from Näräjaa, Ponérihouen (http://endemia.nc); D, J.-N. Labat 3486 (P).