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

description: Gossia clusioides (Brongn. & Gris) N. Snow
(Figs 7-11)
Austrobaileya 8: 180 (2010). — Eugenia clusioides Brongn. & Gris, Bulletin de la Société botanique de France 12: 180 (1865). — Austromyrtus clusioides (Brongn. & Gris) Burret, Notizblatt des Botanischen Gartens und Museums zu Berlin-Dahlem 15: 503 (1941). — Typus: New Caledonia. Grande Terre, South Prov., Deplanche 525 (holo-, P [P00602545]).
ETYMOLOGY. — Derived from the generic name Clusia L. (Clusiaceae) given the resemblance of its leaf blades to many species of that genus.
DISTRIBUTION, HABITAT AND PHENOLOGY. — Across much of Grande Terre (Fig. 7); in humid or gallery forests over micaschistes, graywackes, or ultramafics, 10- 900 m. Flowering December to June; fruiting January to November.
DESCRIPTION
Trees or shrubs
(0.5-)3-9(-15) m tall.
Branchlets
Round to compressed; internodes> 5 mm.
Leaves
Coriaceous, 2 per node; petioles 3.5-20 mm, slightly sulcate; blades 7.0-18.5 × 2.5-12.0 cm, narrowly elliptic to broadly elliptic or obovate, base cuneate or rounded, surface flat to strongly bullate, margin flat to revolute, apex obtuse to sometimes retuse, midnerve above strongly sulcate, secondary veins flush to impressed above, oil glands of lower surface sparse to common but indistinct.
Inflorescence
90-160 mm; of monads, cymes, racemes, or panicles, terminal or axillary, pedicels 0.7-2.0 cm; extrafloral bracts leafy and pronounced when present but soon deciduous.
Bracteoles
6-7 mm, narrowly ovate to ovate, sparsely sericeous. Hypanthium
4-5 × 6-11 mm, campanulate, surface smooth, sparsely sericeous to sericeous (trichomes sometimes reddish at base); ovary apex glabrous.
Calyx
Lobes 5, 2.5-4.5 mm, broadly ovate to rounded, sericeous above (sometimes densely so), sparsely sericeous below, green.
Petals
9-11.5 × 7-9 mm, glabrous above, sericeous-tomentose below (trichomes reddish at base).
Filaments
6-8 mm; anther sacs 0.6-1.0 mm.
Style
Up to 9 mm, glabrous.
Fruits
7-17 × 7-15 mm, globular, base rounded to tapered, dark bluish-black; seeds 1-3.
REMARKS
Gossia clusioides has large flowers and small leafy bracts in the inflorescences that typically are soon caducous; the species also can be diagnosed by the strongly sulcate midveins on the upper leaf surface. It is one of several species in which the epidermis begins to crack into dark, irregularly rectangular flakes during the second year of growth.
Herbarium labels indicate that some members are slender and somewhat sparsely branched. Specimens with large (nonbullate) leaves might be confused with of G. aphthosa, but the flowers and fruits of G. clusioides are considerably larger.
The species has considerably more variation in leaf morphology than others of Gossia in New Caledonia. As treated here, Gossia clusioides comprises nine subspecies that are separated based primarily on differences in leaf dimensions and texture (smooth versus bullate), edaphic preferences, and often (but not always) geographic isolation. Some sites, however, have more than one subspecies. Much additional fieldwork is needed to further test the distinctness of the subspecies and to better understand their differences and distributions, especially given that these entities may be undergoing speciation.
KEY TO THE SUBSPECIES OF GOSSIA CLUSIOIDES (BRONGN. & GRIS) N. SNOW
1. Leaf blades moderately to strongly bullate ................................................................................................... 2
— Leaf blades flat (sometimes slightly bullate in subspp. clusioides and taomensis) ............................................ 5
2. Mature leaves (6.5-)7.0- 12.5 cm wide .......................................................................................................... ............................................... Gossia clusioides subsp. ploumensis (Däniker) N. Snow, comb. et stat. nov.
— Mature leaves 3.5-6.5 cm wide .................................................................................................................... 3
3. Leaves ovate to elliptic or broadly elliptic .................... Gossia clusioides subsp. maoyana N. Snow, subsp. nov.
— Leaves narrowly elliptic ............................................................................................................................... 4
4. Leaves 4-7 times longer than wide .......................... Gossia clusioides subsp. avanguiensis N. Snow, subsp. nov.
— Leaves 2-3(-4) times longer than wide .......................... Gossia clusioides subsp. bleuensis N. Snow, subsp. nov.
5. Leaves mostly elliptic to broadly elliptic or obovate (rarely narrowly elliptic in subsp. clusioides) .................. 6
— Leaves narrowly elliptic ............................................................................................................................... 7
6. Leaf blades thickly coriaceous, upper surface often glossy, abaxially secondary veins often somewhat distinct, margin often strongly recurved nearly throughout; southwestern coast over ultramafics ................................. .......................................................................... Gossia clusioides subsp. callmanderiana N. Snow, subsp. nov.
— Leaf blades coriaceous, upper surface matte, abaxial secondary veins flush or distinct, margins flat to slightly recurved; across much of Grande Terre ......................................................... Gossia clusioides subsp. clusioides
7. Leaves obovate to elliptic, apex obtuse or (usually at least slightly) retuse ....................................................... ................................................................................. Gossia clusioides subsp. rembaiensis N. Snow, subsp. nov.
— Leaves narrowly elliptic, apex obtuse to broadly acute ................................................................................. 8
8. Petioles 2-7 mm long; leaves 3-6 cm long ................... Gossia clusioides subsp. taomensis N. Snow, subsp. nov.
— Petioles 8-20 mm long; leaves 9.5-17 cm long ........ Gossia clusioides subsp. tiebaghiensis N. Snow, 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 144-146, DOI: 10.5252/adansonia2020v42a7, http://zenodo.org/record/3877392