Gossia aphthosa N. Snow
Creators: name: Snow, Neil
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Myrtales
Myrtaceae
Gossia
Gossia aphthosa

description: Gossia aphthosa (Vieill. ex Brongn. & Gris) N. Snow
(Figs 4D-G; 5; 13E-I)
Austrobaileya 8: 180 (2010). — Eugenia aphthosa Brongn. & Gris, Bulletin de la Société botanique de France 13: 469 (1865). — Austromyrtus aphthosa (Brongn. & Gris) Burret, Notizblatt des Botanischen Gartens und Museums zu Berlin-Dahlem 15: 504 (1941).
— Typus: New Caledonia. Grande Terre, South Prov., Collines de Wagap, Vieillard 2172 (holo-, P [P00602542]; iso-, A[A00255453, A00255454], B, BISH, G[G003410963, G00340964], L[3 sheets], MEL, P[P00602543], Z[Z-000050852]).
ETYMOLOGY. — Likely from the Greek aphtha, which is a reference to thrush (= mouth ulcers), coupled with the Latin suffix osa (“full of”). Aphthosa thus presumably refers to the ring of corky tissue at the base of the petioles.
DISTRIBUTION, HABITAT AND PHENOLOGY. — In three distinct regions areas on Grande Terre (Fig. 5); in gallery forests and other humid to wet forests over ultramafics, schists, micaschists, and gneiss, 250- 500 m. Flowering August through February; fruiting September through June.
DESCRIPTION
Trees or shrubs
2- 8 m.
Branchlets
Terete to compressed; internodes> 5 mm.
Leaves
Coriaceous, 2 per node; petioles 2-4.8 mm, flat to terete; blades (8.5-)12.0-24.0 × (3.5-)6.6-13.0 cm, elliptic to broadly elliptic, base cordate (and sometimes amplexicaulous) to broadly rounded, surface flat, margin flat to somewhat revolute at edges, apex obtuse to somewhat acute, midnerve above sulcate, secondary veins flush above, oil glands of lower surface dense but indistinct.
Inflorescence
1.5-6 cm, of monads, triads, or few-flowered racemes, axillary or clustered on naked branches; pedicels 0.3-1.5 cm; extrafloral bracts lacking or scale-like.
Bracteoles
(1.5-) 3-4 mm, very narrowly ovate or elliptic to very narrowly obovate, sparsely sericeous.
Hypanthium
c. 1.5 × 1.5 mm, campanulate, surface smooth, glabrous to densely sericeous; ovary apex glabrous.
Calyx
Lobes 4 or 5, 1- 2 mm, broadly triangular, sparsely sericeous above, glabrous to sparsely sericeous below, green.
Petals
c. 5 × c. 4 mm, glabrous above and below, ciliate on margins.
Filaments
5-8 mm; anther sacs 0.4-0.5 mm.
Style
6-7 mm, glabrous to sparsely sericeous at base.
Berry
8-9 × 8-9 mm, globular, base rounded, green maturing becoming dark purplish to blackish; seed number unknown.
REMARKS
Gossia aphthosa can be distinguished among New Caledonian congeners by its relatively large, flat, and broadly rounded to cordate leaf bases and frequently cauliflorous inflorescences.The nominal subspecies has a prominent ring of corky tissue at the base of the petioles, which is unique in the genus (e.g., Snow et al. 2003). The three subspecies are based on differences in eco-geography and non-fixed, but mostly consistent differences in morphology. The inflorescence branches are said to be reddish on some specimens (e.g., MacKee 13229) and the leaves are said to emerge pinkish (MacKee 4427).
KEY TO THE SUBSPECIES OF GOSSIA APHTHOSA (VIEILL. EX BRONGN. & GRIS) N. SNOW
1. Base of petiole surrounded by prominent ring of corky tissue; hypanthium often silvery-sericeous (northern late Cretaceous micaschistes and gneiss, Massif du Panié, Northern Province) ................................................ ...................................................................................................................... Gossia aphthosa subsp. aphthosa
— Base of petiole without corky swellings; hypanthium mostly glabrous (northern Central Range basement Mesozoics ands schistes) ...................................................................................................................................... 2
2. Inflorescences 5-8 cm; leaf blades stiffly coriaceous, base strongly cordate and clasping; north-central humid forests ........................................ Gossia aphthosa subsp. longipedunculata N. Snow & Munzinger, subsp. nov.
— Inflorescence less than 6 cm; leaf blades coriaceous, base rounded or cordate and clasping; southeast humid forests over ultramafics ................ Gossia aphthosa subsp. austro-orientalis N. Snow & K. Gandhi, subsp. nov.
description: Published as part of Snow, Neil, 2020, A revision of New Caledonian Gossia N. Snow & Guymer (Myrtaceae), pp. 131-177 in Adansonia (3) (3) 42 (7) on pages 139-140, DOI: 10.5252/adansonia2020v42a7, http://zenodo.org/record/3877392