Geijera tartarea T.G.Hartley ex Munzinger & Bruy, 2023

Bruy, David, Lannuzel, Guillaume, Gâteblé, Gildas & Munzinger, Jérôme, 2023, Three new species threatened by mining activity in New Caledonia, Phytotaxa 578 (3), pp. 228-240 : 233

Geijera tartarea T.G.Hartley ex Munzinger & Bruy sp. nov. ( Figs. 4 , 5 )

Type:— NEW CALEDONIA. Province Nord. Voh: Katépahié , 238 m, 20°55’54.78”S, 164°41’33.47”E, 10 November 2021 (fr.), Bruy, Lannuzel & Pouget 2107 (Holotype: NOU108590 !, isotypes: GOET!, MPU1379611 !, NOU108637 !, P!, TNS!) .

Diagnosis:— Geijera tartarea is distinguished by its predominantly 4-merous flowers, its red-purplish calyx (in vivo), by its follicles, which have a rough and crumbly exocarp, and its short petioles (1–5 mm long).

Branched shrub 1–3.5 m high, reaching 6 cm in DBH, conforms to the Rauh architectural model ( Hallé et al. 1978) with a well-differentiated trunk. Twigs gray, glabrous, with bark longitudinally cracked. Stipules absent. Leaves simple, spirally arranged; blades obovate to narrowly elliptic, 2.2–6.5 × 1–4.4 cm, dark green adaxially, greenyellowish abaxially, coriaceous, plane, glabrous; base obtuse to acute or cuneate; apex rounded or obtuse, often retuse or emarginate; margin irregular; oil-dots evident on the adaxial and abaxial sides (in vivo and in sicco), ca. 50 µm in diameter, 15–20 per mm². Midrib barely raised adaxially and abaxially; secondary and tertiary veins obscure or not visible. Petioles without pulvinus, circular to slightly flattened adaxially in cross section, 1–5 mm long, 0.5–1.2 mm in diameter, concolor with the twigs, glabrous. Inflorescences cymulose, (inter-) infrafoliar, 1- or few-flowered, 3–3.5 mm long (in fruit 0.8–1 cm long). Flowers 4(–5)-merous, sessile, haplostemonous; calyx ca. 0.8 mm long, hairy at base, red-purplish (in vivo) contrasting with the corolla, usually rupturing between lobes, lobes rounded or broadly ovate–triangular, ca. 0.3 × 0.5–0.8 mm, ciliate, aestivation open; corolla glabrous, yellowish to pale green, petals rhomboid with an obtuse apex, domed, 1.5–2 × 1–1.5 mm; stamens glabrous, anthers 0.3–0.4 × 0.3 mm, filaments markedly curved, ca. 0.6 × ca. 0.15 mm; gynoecium ca. 0.8 mm long, 4–5-carpelled, each carpel uni-ovuled, ovaries hispidulous, ca. 0.6 mm long, style absent, stigma irregularly shaped, ca. 0.2 × 0.2 mm. Fruit a polyfollicle of 1–2 fruiting carpels, each follicle (spherical)–ellipsoid, 6.5–7 × 5.5–6.5 mm; exocarp rough and crumbly, pale brown, without indumentum; seeds ellipsoid ca. 5 × 4 mm, testa shiny black.

Phenology:—Flowers of Geijera tartarea have been observed in January, April–May and August, and fruits have been collected from April to December. Interestingly, the only two individuals known to the authors are not fertile at the same time while growing side by side: one bore fruit in November 2021 and in April 2022 while the other was sterile in November 2021 and in flower in April 2022. This suggests that the first individual might be female and the second male, the species being functionally dioecious. In contrast, Dagostini 757 shows a fruit and flowers with well developed stamens and open anthers. We did not observe any obvious dimorphism in the flowers, but we believe that the sexual system of the plant needs further study.

Distribution and Ecology:—This new species is endemic to the west coast of the Province Nord. It is known from five localities between Vavouto in the municipality of Voh and Paagoumène in the municipality of Koumac ( Fig. 3 ). Geijera tartarea occurs in dense shrubby maquis on serpentinites, between 5 and 500 m elevation. It seems not to be common in its habitat.

Etymology:—The species is named tartarea because of its fruit which has a rough and crumbly (tartareous) surface.

Species recognition:— Geijera tartarea is remarkable by its follicles, which have a rough and crumbly exocarp, and its red-purplish calyx (in vivo), contrasting with the yellowish corolla.

Conservation status:— Geijera tartarea is known from five populations, three of which are located on or near mining concessions. The only population known to the authors today has a very low density and some previously reported populations may have been lost due to mining activity (Vavouto for example). The EOO calculated is 316 km ² and the AOO is 28 km ². Consequently, G. tartarea has been assigned a conservation status of Endangered (EN) B1 ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v) by the New Caledonian Red List Authority on 20/07/2022 (Endemia & RLA Flore NC, 2022).

Additional specimens examined (Paratypes): — NEW CALEDONIA. Province Nord. Voh. Katépahié , 239 m, 20°55’54.65”S, 164°41’33.01”E, 22 April 2022 (fl.), Bruy & Munzinger 2329 ( GOET, K, MPU1379612 , NOU108593 , P) ; Katépahié , 238 m, 20°55’54.78”S, 164°41’33.47”E, 22 April 2022 (fr.), Bruy & Munzinger 2330 ( NOU108592 ) ; Koumac. Siounda, quelques centaines de mètres au Sud du SMA, 22 January 2004 (fl.), Dagostini, Fambart-Tinel & Roumagnac 757 ( CANB, MO, NOU002870 , P04759896 ) ; Voh. Vavouto , 45–100 m, 18 December 2002 (fr.), Jaffré & Roumagnac 3581 ( NOU014280 , P) ; Voh. Vavouto , 11 February 2003 (st.), Jaffré, Fambart & Roumagnac 3648 ( NOU014506 ) ; Voh. Katépahié , 300–500 m, 15 June 1970 (fr.), MacKee 22037 ( NOU024092 , P00543982 ) ; Voh. Presqu’Île de Gatope , 200 m, 27 June 1970 (fr.), MacKee 22088 ( NOU038343 , P00226444 ) ; Voh. Presqu’Île Gatope , 15 August 1970 (bt., fl.), MacKee 22402 ( NOU038360 , P00226443 ) ; Koumac. Paagoumène , 5 m, 21 December 1981 (fr.), MacKee 40136 ( CANB 719134.1 , NOU038341 , P04759921 ) ; Koumac. Kokondo , 30 m, 9 January 1983 (fl.), MacKee 41182 ( CANB, NOU038359 ) ; Koumac. Paagoumène , face site de l’usine, 13 May 1981 (fr.), Veillon 4480 ( NOU090292 ) .

Figures

FIGURE 3. Distribution map of Croton barrabeae (black large dots), Geijera tartarea (black pentagons) and Tristaniopsis planidisca (grey squares). The T’s represent the locality of the type specimens for each species. The black triangles represent the two highest mountains in New Caledonia. The small black dots represent the main cities in the South Province and the North Province. Grayed areas represent ultramafic substrates (from DIMENC/SGNC-BRGM 2010).

FIGURE 4. Pictures of Geijera tartarea. A—Habitat: maquis arbustif; B—Aspect of the leaves (Bruy et al. 2107); C—Abaxial face of a leaf (Bruy et al. 2107); D—Flowering branch (Bruy & Munzinger 2329); E—Flowers (Bruy & Munzinger 2329); F—Fruiting branch (Bruy & Munzinger 2330); G—Fruiting carpel with tartareous surface (Bruy et al. 2107); H—Seed (Bruy et al. 2107). Photographers: Lannuzel G. & Munzinger J.

FIGURE 5. Drawing of Geijera tartarea. A—Fruiting branches; B—Abaxial (left) and adaxial (right) sides of the leaf with detail of oildots; C—Apical buds; D—Flowering twig; E—Flower bud; F—Flower seen in profile; G—Flower seen from the front; H—Adaxial (left) and abaxial (right) sides of a petal; I—Stamen; J—Gynoecium; K—Fruit; L—Seed.