Parsonsia tiebaghiensis Gâteblé, 2025

Lannuzel, Guillaume, Bruy, David, Munzinger, Jérôme, Vandrot, Hervé & Gâteblé, Gildas, 2025, Synonymy, nomenclature and taxonomic notes in New Caledonian Parsonsia (Apocynaceae), with the description of four new species, Phytotaxa 710 (2), pp. 131-164 : 156-160

Parsonsia tiebaghiensis Gâteblé , sp. nov. ( Figs. 14 , 15 & 16 ) (urn:lsid:ipni.org:names:77359148-1)

Diagnosis: — Parsonsia tiebaghiensis is most similar to P. flexilis , P. bogotensis and P. urceolata with its inserted stamens but differs from the former by its corolla and calyx glabrous outside. Among the species with inserted stamens and glabrous corolla, it is the only one to present a ring of hairs within the corolla, instead of rows of hairs.

Type: — NEW CALEDONIA. North province: Paagoumène, Koumac ,elev. 42m, 20°28’43.49’’S, 164°10’49.85’’E, 20 February 2022, Fleurot D. & Dayé P. 924 (holotype NOU [ NOU092395 !]; isotypes P!, MPU313248 !, VTA064433 !, VTA064434 !, VTA064435 !) .

Small climber with twining stems, stems up to 2 meters long, up to 3 mm in diameter, young stems glabrous; latex white. Leaves opposite or ternate, subcoriaceous, green on both surfaces, petiole (1.6–)2–2.6(–3.5) mm long, 0.6–1 mm wide, usually green, covered with short hairs on adaxial surface, tooth-like colleters, two on each side of petiole, sometimes absent; lamina almost linear, (24.4–)33.9–56.3(–62) × (3–)3.6–4.2(–5.2) mm; rounded at base, apex acute and mucronate, both surfaces glabrous, leaf venation brochidromous, with secondary veins visible on both surfaces on dry and living material. Inflorescence an axillary composed cyme 6–14-florous, axes green, primary axes (6–)7.5 × 14.5(–27) mm long, puberulent, pedicels (5.7–)6.7–8.6(–9) mm long, glabrous to puberulent, bracts ca. 0.5 mm, narrowly lanceolate.

Flower 5-merous, narrowly urceolate, (5.5–)6.1–6.6(–6.7) × (1.5–)1.6–1.9(–2.2) mm. Calyx lobes appressed to corolla, deltoid, acute at apex, (0.6–)0.6–0.8(–1) × ca. 0.7 mm, creamy white, glabrous. Corolla creamy white, tube (4.2–)4.4–4.5(–5.2) × (2–)2.1–2.2(–2.3) mm, glabrous outside, with a ca. 1 mm wide ring of hairs, composed of ca. 0.5 mm long retrorse hairs at halfway of corolla in the tube, lobes narrowly lanceolate, glabrous, spreading, (1.2–)1.6– 1.7(–1.8) × ca. 1 mm.

Anther cone ca. 1.9 mm long, not exserted; filaments ca. 1.4 mm, hairy on abaxial surface. Ovary ovoid, ca. 0.8 × 0.5 mm, glabrous, circled by 5 glabrous scales ca. 0.7 × 0.5 mm. Style glabrous ca. 1.8 mm long, stigmate fusiform ca. 0.4 mm long.

Fruit cylindrical, ca. 5 × 0.8 cm, acute to acuminate at apex, glabrous.

Distribution and habitat: —The species is known from two localities, the lower slopes of Tiebaghi and Ouazangou mountains. It grows in shrubland on serpentine substrates.

Phenology: —The phenology of this species is poorly known. From known observations, flowers can be seen from February to April, and November, and fruits in February and November.

Etymology: —The species is named after the Tiebaghi massif where the only modern observations were made.

Conservation status: The species has been evaluated as Endangered by the RLA-NC on 28/09/2022. It is considered as threatened mostly by bushfires and mining activities.

Notes: —The specimens Mackee 14558, 16618 and 21661 were listed under P. effusa in a special paragraph regarding its putative neotenic form in Boiteau (1981: 262). Allorge also determined them as Parsonsia cf. effusa in herb. in 1979. Among the other specimens listed in this paragraph, Mackee 21993 (P04216086) is Leichhardtia neomicrostoma ( Meve et al. 2018: 208) Liede-Schumann et al. (2020: 132) .

Specimens examined: — NEW CALEDONIA. North province: Paagoumène , elev. 20–100 m, 16 March 1966, Mackee 14558 ( P04216089 !d) ; Néhoué, ancienne mine Fantoche , elev. 50–100 m, 20 April 1967, Mackee 16618 ( NOU058977 !, P04216093 !d) ; Pente W du Mt Ouazangou , elev. 200–500 m, 11 September 1967, MacKee 17523 ( NOU058982 !) ; Paagoumène , elev. 30 m, 27 February 1970, Mackee 21661 ( P04216085 !d) .

Parsonsia urceolata Gâteblé, Lannuzel & Vandrot , sp. nov. ( Figs. 14 , 17 & 18 ) (urn:lsid:ipni.org:names:77359149- 1)

Diagnosis: — Parsonsia urceolata is most similar to P. flexilis , P. bogotensis and P. tiebaghiensis with its inserted stamens but differs from the former by its corolla and calyx glabrous outside. Among the species with inserted stamens and glabrous corolla, it differs from P. tiebaghiensis by its rows of hairs inside the corolla, and from P. bogotensis by its leaves tomentulose on both side and with a shorter petiole.

Type: — NEW CALEDONIA. North province: Massif de Poum , route de l’antenne, elev. 121 m, 20°14’19.58’’S, 164°1’56.45’’E, 4 May 2021, Bruy, Gâteblé & Lannuzel 1977 (holotype NOU [ NOU107707 !]; isotypes BM!, L!, NOU [ NOU112238 !], P [ P00942419 !]) .

Small climber with twining stems, stems up to 1.5 meters long, up to 0.8 cm in diameter at the base, young stems glabrous; latex white. Leaves opposite, subcoriaceous, green adaxially, light green abaxially when young and usually tinted with purple when older (on fresh material), both surfaces looking lustrous but tomentulose and covered with very short hairs (ca. 0.01 mm long), shape variable, petiole 1–5 mm long (usually shorter values on elliptic leaves and longer ones on linear leaves), usually reddish to purple, glabrous, tooth-like colleters ca. 0.2 mm long in the leaf axil; lamina of juvenile-like leaves linear, sometimes slightly falcate, 3.5–6 × 0.2–0.5 cm, mucronate; lamina of adult-like leaves elliptic to lanceolate, sometimes slightly falcate, 2.5–4 × 0.8–1.3 cm, cuneate at base, acute to rounded at apex, mucronate, leaf venation faint and usually not visible on dry material (3–5 pairs of secondaries sometimes visible on fresh material) apart from the midrib (sometimes reddish). Inflorescence a loose axillary panicle, axes green to reddish, glabrous, pedicels (0.3–)0.5–0.8(–11) cm long, glabrous, bracts lanceolate ca. 0.3 mm.

Flower 5-merous, narrowly urceolate, 5–7 × 2–2.4 mm. Calyx lobes appressed to corolla, lanceolate, acute at apex, 1 mm long, green to reddish, glabrous. Corolla white to greenish, tube 3.5–4 × 2–2.4 mm, glabrous outside, with 5 rows of ca. 0.15 mm long retrorse hairs within corolla from throat to halfway in the tube, lobes lanceolate, glabrous, spreading, 1.5 mm long.

Anther cone ca. 1.7 mm long, not exserted; filaments ca. 0.5 mm long, hairy on abaxial surface. Ovary ovoid, ca. 0.7 × 0.5 mm, glabrous, circled by 5 glabrous scales ca. 0.5 × 0.3 mm. Style glabrous ca. 1.8 mm long, stigmate fusiform ca. 0.3 mm long.

Fruit narrowly cylindrical, ca. 5 × 0.4 cm, acute to acuminate at apex, glabrous.

Distribution and habitat: — Parsonsia urceolata is only known from a small population on the northern slope of the Poum mountain. It grows in open shrubby maquis, at low elevation, on peridotite substrate.

Phenology: —This species is poorly known and has been seen flowering and fruiting only in May and June.

Etymology: —The name urceolata refers to the typical corolla shape of the species.

Conservation status: —The species has been evaluated as Critically Endangered by the RLA-NC on 28/09/2022. The only known population is indeed highly threatened by bushfires.

Specimens examined: — NEW CALEDONIA. North province: Massif de Poum , elev. 130 m, 20°14’22.25’’S, 164°1’55.6’’E, 26 June 2014, Gâteblé 494 ( NOU052037 !, NOU052038 !, NOU052039 alc.]) ; Massif de Poum , vers l’antenne au dessus du village, elev. 130 m, 20°14’19.12’’S, 164°1’55.17’’E, 4 May 2021, Gâteblé, Lannuzel & Bruy 1272 ( NOU107858 !, P00942227 !) .

Figures

FIGURE 14. Known repartition of Parsonsia tiebaghiensis (squares) and Parsonsia urceolata (dots). Symbols with “T” represent type specimens. Grayed areas represent ultramafic substrates.

FIGURE 15. General habit of Parsonsia tiebaghiensis (A) with detail on inflorescences (B), flower (C), and a fructifying branch (D). Credit: D. Fleurot. Pictures corresponding to Fleurot 924.

FIGURE 16. Drawing of Parsonsia tiebaghiensis. A—Flowering branches with details of inflorescence (B), venation (C) and petiole insertion with colleters (D); E—Flower; F—Longitudinal section of the flower; G—Flower from above; H—Fructifying branch with open fruit; I—Fruit with detail of calyx remnants (J).

FIGURE 17. Flowering branch of Parsonsia urceolata (A), with detail of inflorescence (B), flower (C) and fruits (D). Credit Lannuzel G. (A–C), Gâteblé G. (D). Pictures correspond to Gâteblé 1272 (A–C), and Gâteblé 494 (D).

FIGURE 18. Drawing of Parsonsia urceolata. A—Flowering branches; B—Colleters at petiole insertion; C—Fruit; D—Flower from above; E—Flower; F—Flower longitudinal cutting.