Delarbrea balansae (Baill.) Lowry & Plunkett

Lowry Ii, Porter P., Plunkett, Gregory M., Raquet, Virginie, Sprenkle, Taylor S. & Jérémie, Joël, 2004, Inclusion of the endemic New Caledonian genus Pseudosciadium in Delarbrea (Apiales, Myodocarpaceae), Adansonia (3) 26 (2), pp. 251-256 : 254

Delarbrea balansae (Baill.) Lowry & Plunkett , comb. nov.

Pseudosciadium balansae Baill., Adansonia 12: 130 (1878). — Lectotype (here designated): Balansa 3380, New Caledonia, bosquets situés près de l’embouchure du Dotio (= Dothio), [21°35’S, 166°12’E], Dec. 1871, fl. (P!; iso-, MO!, NOU!, P (3 sheets)!).

Trees 2-4 m tall. Leaves 25-40(-50) cm long; leaflets 9-15, membranous, ovate to ovateelliptic, often narrowly so, 5-12.5 × 2-5 cm, the lowermost somewhat reduced and often broadly ovate, apex narrowly obtuse to acuminate, minutely mucronate, margin entire, to serrate on the first few leaves of new shoots (finely and more deeply serrate in juvenile foliage), base obtuse to truncate; petiolules 7-15 mm long, flattened laterally, with the scarious margins upturned and forming a groove on the top; petiole terete, with an evident thickening c. 1 cm from the base, usually glaucescent. Inflorescence light yellow-green throughout, primary axis (55-) 65-150 cm long, pendant, glaucescent at the base, secondary axes 10-15, alternate, regularly scattered and borne at 45-90° angle to the primary axis, the lower ones up to 40 cm long, reduced progressively toward the apex, tertiary axes 8-12 per secondary axis (fewer on the upper ones), alternate, 3-9 cm long (the uppermost somewhat smaller), each with a terminal umbellules of 4-10(-12) hermaphrodite flowers and (0-)1-4 small lateral umbellules of 1-8 staminate flowers, involucre minute, of 4-6 triangular, acuminate bractlets each 0.5-1 mm long (smaller in staminate umbellules), pedicels 3-7 mm long (those of the staminate flowers 1.5-4 mm long). Petals yellow-green, c. 0.7 mm long (smaller in staminate flowers). Filaments yellow-green, 0.8 mm long, anthers 0.6 mm long (0.4-0.5 mm in staminate flowers). Ovary 0.8-1 mm long at anthesis, styles 0.6- 0.8 mm long at anthesis (0.4 mm long and vestigial in staminate flowers), expanding very little in fruit, but becoming somewhat thicker. Fruit ellipsoid-ovoid, olive-green turning deep purple when mature, 10-13 mm long, smooth, shiny, nearly always crushed in pressed specimens. 2n = 24 ( LOWRY 1986b; YI et al. 2004). — Fig. 1.

HABITAT. — Delarbrea balansae appears to be restricted to ultramafic substrates in southern New Caledonia, and occurs primarily in humid forests, although one collection has been made in maquis vegetation (see LOWRY 1986b). The species has only been recorded at five sites, four at low elevation (0-50 m) along or near the east coast (one on the Baie de Ouinné and three in the region of Thio) and one at about 450 m on Mt. Mou, NW of Nouméa.

CONSERVATION STATUS. — Using the IUCN (2001) threat criteria, Delarbrea balansae is assigned a preliminary status of Endangered (EN B1ab2abD) based on the fact that it has an Extent of Occurrence of c. 1000 km 2, an Area of Occupancy <100 km 2 (known from just five locations), and an estimated total population of less than 250 mature individuals.

MATERIAL EXAMINED. — NEW CALEDONIA: Prov. Sud : Achille 845, Port Bouquet , rivière Neuméni , près du pont, forêt galerie, terrain ultramafique, [21°39’S, 166°19’E], 20 m, 21 Mar. 2000, fr. (P); Lowry 3548, Mt. Mou, NNW of Païta, c. 25 km NW of Nouméa, trail to summit above road to Sanatorium, dense forest along trail, peridotite, 22°04’33”S, 166°20’05”E, 450 m, 25 Oct. 1984, fr. (MO, NOU, P); Lowry 3549, same locality and date, juv. (MO, NOU, P); Lowry 3635, same locality, 20 Dec. 1984, bud, fl. (MO, NOU, P); Lowry 3663, same locality, 6 Jan. 1985, fl. (MO, NOU, P); Lowry 3799, same locality, 24. Feb. 1985, y. fr. (MO, NOU, P); Lowry 3865, same locality, 28 Nov. 1985, bud, fl. (MO, NOU, P); Lowry, Plunkett & Oskolski 4714, same locality, 8 Dec. 1996, bud (MO, NOU, P); Lowry, Plunkett & Sprenkle 5522, same locality, 6 Mar. 2002, fr. (MO, NOU, P); MacKee 28732, Baie de Ouinné , Ué, forêt galerie sur alluvions serpentineuses, [21°59’S, 166°40’E], 2 m, 26 May 1974, fr. (G, MO, P); MacKee 28733, same locality and date, juv. (MO, NOU, P); MacKee 28873, base ouest du Mt. Mou , ravin boisé en terrain serpentineux, [22°04’S, 166°20’E], 400 m, 4 July 1974, fr. (G, MO, P); Morat 6363, piste de la forêt de Saille, bord de rivière, [21°40’S, 166°11’E], Mar. 1979, fr. (NOU, P); Schmid 2766, route de Thio à Port-Bouquet (au passage de la rivière Neuméni), maquis sur pente péridotitique au voisinage de la rivière, [21°39’S, 166°19’E], 50 m, 1 Apr. 1969, fr. (P); Schmid 4927, Mt. Mou , versant Sanatorium , [21°59’S, 166°40’E], 450 m, 12 Jan. 1974, fl. (NOU, P); Veillon 2680, haute vallée de la Nimbrou , fourré hallier à la base de la montagne en bordure de la rivière, [21°40’S, 166°11’E], 50 m, 24 July 1972, fr. (NOU); Veillon 4720, creek Neuméni, [21°39’S, 166°19’E], 16 Dec. 1981, fl. (NOU).

Figures

FIG. 1. — Delarbrea balansae (Baill.) Lowry & Plunkett: A, flowering branch;B, juvenile leaf; C, flower at anthesis (side view); D, flower at anthesis (top view); E, fruit; F, portion of an infructescence. A, C-D, Lowry 3663; B, Lowry 3549; E, F, Lowry 3548.