Gossia mandjeliaensis N. Snow, 2020

Snow, Neil, 2020, A revision of New Caledonian Gossia N. Snow & Guymer (Myrtaceae), Adansonia 42 (7), pp. 131-177 : 161-162

Gossia mandjeliaensis N. Snow , sp. nov. ( Figs 15I-J ; 17 )

The leaves resemble those of Gossia vieillardii , but the oil glands on the lower leaf surface of G. mandjeliaensis sp. nov. are conspicuous and dense and the base of its hypanthium somewhat rounded.

TYPUS. — New Caledonia. Grande Terre , North Prov. , Forested slopes below radio tower of Mandjélia, c. 5 air-km W of Pouebo, 20°23’58.99”S, 164°31’30.00”E, 12.IV.1980, McPherson 2551 (holo-, P [ P00402744 ]; iso-, BISH, MO[ MO-3226084 ], NOU [ NOU030914 ], WELTU).

PARATYPI. — McPherson 6327, Mandjélia, above Pouébo, 20°24’18.40”S, 164°31’05.00”E, c. 650 m, 21.II.1984 (MO[MO-3225874], NOU[NOU029639], P[P00462929], WELTU).

REPRESENTATIVE HERBARIUM SPECIMEN. — P00402744. ETYMOLOGY. — After the type locality.

DISTRIBUTION, HABITAT AND PHENOLOGY. — Known only from Mt. Mandjélia ( Fig. 17 ); forested slopes over metamorphic rock, 600- 650 m. Flowering February through April; fruiting period unknown.

DESCRIPTION

Trees

To 10 m.

Branchlets

Terete; internodes> 5 mm. Leaves

Coriaceous, 2 per node; petioles 2-3 mm, sometimes slightly sulcate; blades (1.5-)3.0-6.0 × (-1.0)2.0-4.0 cm, narrowly elliptic to broadly elliptic, base cuneate (or occasionally rounded), surface flat, margin flat, apex obtuse to acute, midnerve above sulcate near base but becoming flush distally, secondary veins faint and flush above and below, oil glands dense but typically indistinct above and below.

Inflorescence

Up to 3.5 cm, of monads, simple cymes, or few-flowered racemes, axillary or terminal, pedicels 0.1-0.8 cm; extrafloral bracts absent or scale-like.

Bracteoles

1.5-3 mm, linear, very narrowly elliptic, or narrowly obovate, more or less sericeous.

Hypanthium

3-4 × 3-4 mm, campanulate, surface smooth, sericeous; ovary apex sparsely hairy.

Calyx

Lobes 5, 1.3-1.9 mm, broadly rounded, glabrous above, sericeous near base below and ciliate on edges, green.

Petals

4-5 × 4-5 mm, glabrous above, glabrous to sparsely sericeous below.

Filaments 3-5 mm; anther sacs 0.5-0.6 mm.

Style c. 5 mm, sericeous at base.

Fruits

Dimensions unknown, said to be green, mature fruit unknown; seeds not seen.

REMARKS

Gossia mandjeliaensis sp. nov. differs from other New Caledonian congenerics by subtle traits, including the dense but small oil glands on the leaf surfaces; a glabrous to slightly hairy staminal disk; sericeous indumentum on the pedicels, abaxial surface of calyx lobes, and style; and faint abaxially secondary leaf veins. Gossia colnettiana is somewhat similar, but has fewer oil glands abaxially, raised abaxial secondary veins, ferrugineous sericeous hairs in flower, and a hairy staminal disk.

Figures

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. 17. — Distribution maps of G. kaalaensis N. Snow, sp. nov., G. mandjeliaensis N. Snow, G. nigripes (Gullaumin) N. Snow, and G. ouazangouensis N. Snow, sp. nov.