Eugenia tiwakaensis 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 : 76

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

( Fig. 1 , 6 ).

Typus: New CaledoNia. Prov. Nord: Basse Tiwaka , 10 m, 1.I.1979, MacKee 36340 (holo-: P [ P04722500 ]!).

Distinct among congenerics in New Caledonia by its cordate to basally rounded, petiolate leaves, secondary veins arising from ca. 10-20̊ angles, glandular abaxial leaf surfaces, raised adaxial midrib, and sparsely to moderately densely short-villous ferrugineous indumentum of the inflorescence axis and flowers.

Shrubs to 2 m. Indumentum (where present) ferrugineous, sparsely to moderately short-villous (“hairy” below). Branchlets rounded to slightly compressed, moderately to densely short-villous (trichomes ferrugineous at base but often clear or whitish apically), the epidermis sometimes slightly furrowed longitudinally and soon becoming flaky. Leaves petiolate, coriaceous, venation brochidodromous, glabrescent, slightly discolorous, surfaces matte or somewhat glossy above, evenly distributed along branchlets. Foliar colleters not seen. Petioles 4-7 mm, sulcate above, eglandular. Leaf blades 10.0-14.6 X 3.5-5.7 cm, narrowly elliptic to narrowly ovate, base rounded or cordate, apex acute, margin flat; adaxial surface glabrescent near base but otherwise glabrous, eglandular, midvein narrowly and slightly projecting proximally but becoming flush distally, secondary and tertiary veins prominent and slightly projecting (dried material); abaxial surface glabrous, oil glands common and distinct; secondary veins prominent, intramarginal vein prominent and 3-6 mm from margin at midpoint of blade (also visible adaxially). Inflorescences terminal, axillary or ramiflorous; flowers solitary, paired, fascicled, or in short brachyblasts. Peduncles 4-12 mm, rigid, more or less ascending, hairy. Bracteoles 2, 1.0- 1.2 mm, triangular, ascending to erect and appressed against hypanthium, glandular above, hairy, soon deciduous. Hypanthium 3-4 mm, obconic, prominently glandular, sparsely to moderately hairy. Calyx lobes 4, 2- 3 mm, broadly rounded, prominently glandular, ciliate and sparsely hairy below. Petals 4, 5- 9 X 3-5 mm, obovate, sparsely short ciliate, glands sparse. Stamens ca. 75-125, multiseriate; filaments 5-8 mm; anthers 1.0- 1.2 mm, globose to subellipsoid, sub-basifixed, eglandular; staminal disc short-villous. Ovary apex (surrounding style) glabrous. Style length not confirmed (but glabrous below). Fruit not seen but said to be reddish.

Distribution and ecology. ‒ Eugenia tiwakaensis at present is known only from two collections near the northwest coast, growing in a transitional zone between schistes and serpentines or over ultramafics from ca. 10 m to an unspecified “middle altitude” (Vandrot 629) on Tiwaka ( Fig. 2 ). Flowering in January, fruiting in September.

Conservation status. ‒ The recent collection (Vandrot 629) indicates the species is a common local shrub in a very small patch of remnant forest of ca. 2,931 ha. on a plateau that was nearly completely burned. The MacKee locality “basse Tiwaka, 10 m ” is vague, but this general area has been burned widely and intentionally during political protests over the past 35 years. With only three recent collections from a single reliable location in a highly threatened forest remnant, E. tiwakaensis is assigned a preliminary IUCN conservation status of “Critically Endangered” [CR B1ab(v)+2ab(v) +2(a) +D].

Notes. ‒ Eugenia tiwakaensis most closely resembles E. sicifolia , although the triangular bracteoles and broadly rounded calyx lobes of E. tiwakaensis differ from the linear and proportionally longer bracteoles and acute calyx lobes of E. sicifolia . A note on the holotype label indicates the plant was frequented by bees.

Paratypus. ‒ New CaledoNia. Prov. Nord: Tiwaka , Plateau de Kokingone , 29.IX.2012, 165°13’57’’E 20°51’35’’S, 365 m, Vandrot 629 ( NOU [ NOU079951 ], P [ P02089724 ]).

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. 6. – Holotype of Eugenia tiwakaensis J. W. Dawson & N. Snow. [MacKee 36340, P] [© Muséum national d’Histoire naturelle, Paris. Reproduced with permission]