Eugenia tchambaensis J.W. Dawson & N. Snow

Neil Snow, John W. Dawson, Martin W. Callmander, Kanchi Gandhi & Jérôme Munzinge, 2016, New Species, New Combinations, and Lectotypifications in New Caledonian Eugenia L. (Myrtaceae), Candollea 71 (1), pp. 67-81 : 74-76

Eugenia tchambaensis J.W. Dawson & N. Snow , spec. nova

( Fig. 1 , 5 ).

Typus: New CaledoNia. Prov. Nord: Haute vallée de la Tchamba, 350 m, 16.V.1984, Veillon 5691 (holo-: P [ P04722505 ]!; iso-: NOU [ NOU 031551 ]!, MPU [ MPU026760 ]).

Differing from congeneric species in New Caledonia by relatively long, thin, often erect pedicels, relatively short sessile leaves, and distinctly raised midrib of the adaxial leaf surface.

Shrubs 1.3-4 meters. Branchlets glabrous, laterally compressed on emergence, becoming terete. Leaves sessile and clasping stem, coriaceous, venation brochidodromous, glabrous, discolorous, surfaces matte, evenly distributed along branchlets. Foliar colleters absent. Leaf blades (2.0-)4.0-11.4 X (1.3-)2.8- 6.0 cm, elliptic, base cordate and slightly conduplicate basally, apex obtuse, margin flat but surface irregularly sinuous; adaxial surface glabrous, eglandular or faintly glandular (use magnification), midvein raised in lower half of blade and sometimes nearly to the apex; abaxial surface glabrous, eglandular, secondary veins indistinct, intramarginal vein indistinct, 0.5- 1.5 mm from margin at midpoint of blade. Inflorescences terminal, axillary, or occasionally ramiflorous, flowers solitary flowers or occasionally in fascicles. Pedicels (14-) 20-45 mm, narrow (<1 mm wide) but rigid, glabrous, densely glandular, often steeply ascending to nearly erect. Bracteoles 1-1.5 mm, narrowly triangular to triangular, glabrous, glandular, rigid, typically reflexed at 90° angle, persistent in fruit. Hypanthium ca. 2 mm long, cupuliform, glabrous, densely glandular. Calyx lobes 4, 1- 2 mm initially but tearing radially during anthesis and becoming up to 5 mm, broadly rounded, glabrous above and below. Petals 4, 3.5- 5 X 3-4 mm, oblate, minutely ciliate on margin, whitish, glandular. Stamens ca. 75-100, multiseriate. Filaments length unknown; anthers 0.5-0.7 mm, globular to sub-ellipsoid, subbasifixed, eglandular. Styles 3-4 mm, glabrous, narrowly capitate. Fruit 9- 17 X 14-20 mm, subglobose to subcylindrical, rounded or sometimes asymmetrical at base, glabrous, densely glandular (glands small), green (fresh) turning nearly black when dried.

Distribution and ecology. ‒ Known from Tchamba, and vicinity from 350 to ca. 500 meters in humid forest over schistes or graywackes ( Fig. 2 ). Flowering confirmed for January, fruiting January through July.

Conservation status. ‒ The AOO and EOO is estimated to be 16 km 2 with two locations (Haute-Tchamba and ridge between Haute-Monéo and Mou), none in a protected area. Logging is no longer active in that area, E. tchambaensis is therefore assigned a preliminary IUCN conservation status of “Vulnerable” [VUD 2].

Notes. ‒ The relatively short sessile leaves with distinctly raised upper midribs and relatively long, thin, and often erect pedicels collectively are diagnostic. The MacKee specimen occurs at higher elevations (“ 600-700 m ”) and has shorter leaves than the other specimens, but it otherwise accords in all other features.

Paratypi. ‒ New CaledoNia. Prov. Nord: Vallée de la Tchamba , 21°00’20’’S, 165°14’02’’E, 520 m, 13.I.2009, Barrabé et al. 834 ( NOU [ NOU033931 ], P [ P04681808 ]); Upper Tchamba River valley, Pondië forest , along road to Wâo Uni, 21°00’25’’S 165°14’27’’E, 500 m, 27.IV.2002, Lowry et al. 5684 ( MO, P [ P04884671 ]); Ponerihouen, crête entre Haute Mou et Haute Monéo, 21.VI.1973, MacKee 26836 ( P [ P04722504 ]); Haute Tchamba, 21°00’18’’S 165°13’53’’E, 17.VII.2004, Munzinger et al. 2244 ( NOU [ NOU006487 ], P [ P04884649 ]).

Figures

Fig. 1. – Distribution of new species of Eugenia L. in New Caledonia mapped on ultrabasic rocks (light grey) and protected areas (dotted stippling): E. amosensis N. Snow (circle), E. homedeboana N. Snow (squares), E. sicifolia J. W. Dawson & N. Snow (pentagons), E. tchambaensis J. W. Dawson & N. Snow (stars), and E. tiwakaensis J. W. Dawson & N. Snow (crosses).

Fig. 2. – Holotype of Eugenia amosensis N. Snow. [Munzinger et al. 1488, P] [© Muséum national d’Histoire naturelle, Paris. Reproduced with permission]

Fig. 5. – Holotype of Eugenia tchambaensis J. W. Dawson & N. Snow. [Veillon 5691, P] [© Muséum national d’Histoire naturelle, Paris. Reproduced with permission]