Paracephaelis seyrigii De Block 2022, sp. nov.
Creators: name: Block, Petra De
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Gentianales
Rubiaceae
Paracephaelis
Paracephaelis seyrigii

description: Paracephaelis seyrigii De Block sp. nov.
urn:lsid:ipni.org:names:77260716-1
Figs 4H, J, L, O, 20
Diagnosis
Differing from Paracephaelis saxatilis by having larger leaves (2–8.5 × 1.5–5 cm vs 1–4 × 0.7–2.8 cm), longer petioles (0.4–1.5 cm vs 0.2–0.5 cm long), larger stipules (sheath 3–7 mm and awn 0–3 mm vs sheath 1–2.5 mm and awn 0.5–1.5 mm long), larger inflorescences (1–3(–6) × 1.5–3(–6) cm vs 0.6–1.5 × 1–2 cm), and longer calyx lobes (1.5–2 mm long in flowering stage, 3–3.5 mm long in fruiting stage vs 0.8–1.5 mm long).
Etymology
The species epithet honours the French collector, André Seyrig, who was a miner and entomologist (Dorr 1997) and collected the type specimen.
Type material
MADAGASCAR – Toliara Province, Androy Region, Bekily District • Ampandrandava, entre Bekily et Tsivory; 1000 m a.s.l.; Dec. 1943; fl; Seyrig 425; holotype: P; isotype: P, as coll. ignot. (Herbier du Jardin botanique de Tananarive) 5765.
Other material studied
MADAGASCAR – Fianarantsoa Province, Ihorombe Region, Ihosy District • Plateau de l’Horombe, SW du radin sur l’Ilanana; 17 Dec. 1969; fl; Capuron 29029-SF; BR, P • plateaux et vallées de l’Isalo, W de Ranohira; 800–1250 m a.s.l.; 1955; fr; Humbert 28670; P • Ranohira, Isalo PN, Analalava; 18 May 2004; fr; Rakotonasolo & Zachary 783; K, MO, TAN. – Toliara Province, Androy Region, Bekily District • Ampandrandrava, 5 km N of Beraketa; 638 m a.s.l.; 2 Feb. 2006; fr; Andriamahay & Rakotoarisoa 1298; K • Ampandrandava; s.dat.; fr; coll. ignot. (Herbier Jardin botanique de Tananarive) 6439; P • Ampandrandava, entre Bekily & Tsivory; 1000 m a.s.l.; Apr. 1943; fl; Seyrig 425B; P. – Anosy Region, Betroka District • PK 65–66, route Ihosy-Betroka; Feb. 1963; fr; Bosser 17294; BR, P, TAN • rocailles entre Beraketa et Antanimora; 6 Dec. 1961; fl; Capuron 20419-SF; BR, P • road from Beraketa to Betroka, 12 km from Beraketa; 554 m a.s.l.; 9 Feb. 2007; fr; Groeninckx, De Block & Rakotonasolo 237; BR, G, K, MO, P, TAN, TEF, UPS • Betroka, 7 km S of Ianabinda; 790 m a.s.l.; 19 Dec. 2004; fl; Rakotonasolo, Hoffmann, Rakotoarisoa & Ralimanana 933; BR, K, MO, P, TAN. – Atsimo-Andrefana Region, Sakaraha District • Zombitse-Isoky PN, Zombitse; 612 m a.s.l.; 1 Feb. 2007; fl; Groeninckx, Rakotonasolo & De Block 175; BR, G, MO, P, TAN • Zombitse-Vohibasia PN, Isako, W part of Isoky; 4 Dec. 2003; fl; Razafimandimbison & Bremer 498; UPS. – Toliary II District • N d’Andranohinaly, PK 43 de la route Tulear-Sakaraha; 12 Dec. 1962; fl; Capuron 22276-SF; BR, P. – Without locality • s.dat.; fr; Homolle 1610; P.
Description
Shrub or small tree, to 4 m tall; pubescence tawny or, more rarely, whitish. Young shoots pale brown, densely covered with long, appressed or spreading hairs; older branches greyish or brown, glabrous. Leaves grouped at the end of lateral branchlets. Petioles 0.4–1.5 cm long, densely covered with long, erect or spreading hairs. Leaf blades ovate or elliptic, rarely broadly ovate, broadly elliptic or orbiculate, (2–)2.5–8.5 × 1.5–5 cm, thickly coriaceous, drying brown or greenish brown above and somewhat paler below, upper surface densely covered with short to ± long, erect hairs (hairs often somewhat longer and spreading on midrib and secondary veins), lower surface densely covered with long, erect hairs (hairs often more appressed on midrib and secondary veins); base acute, truncate, rounded or somewhat cordate; tip obtuse, acute or broadly acuminate, often mucronate; domatia absent; 5–9 secondary veins on each side of midrib, impressed above, raised below; higher order venation somewhat impressed above, somewhat raised below. Stipules caducous, triangular, keeled, gradually tapering into an obtuse or acute tip or, more rarely, with short needle-like awn; outer surface of youngest stipule pairs densely covered with long appressed or spreading hairs; inner surface glabrous with row of colleters interspaced with long hairs at the base; sheath 3–7 mm long; awn, if present, up to 3 mm long. Inflorescences terminal on short lateral shoots with short internodes and leaves fallen but stipules or stipular remnants remaining, sessile, compact or partial inflorescences compact, 1–3(–6) × 1.5–3(–6) cm, with 15 to numerous flowers; inflorescence parts densely covered with long, spreading or erect hairs; first order axes 0.3–2(–4) cm long; higher order bracts with stipular parts reduced or absent, foliar parts narrowly triangular and vaulted or trilobed, 0.5–1 cm long; bracteoles at base of ovary, opposite, stipular parts absent, foliar parts narrowly triangular, 1.5–2.5 mm long, tips acute. Flowers sessile. Calyx densely covered with ± long, erect or spreading hairs outside, inner surface densely covered with long appressed hairs; tube 0.5–1 mm long; lobes triangular, 1.5–2 mm long in flowering stage, 3–3.5 mm long in fruiting stage, tips acuminate, acute or obtuse. Corolla tube 5–7 mm long, inner surface densely covered with long erect hairs in upper ⅔; lobes 4–5.5 mm long. Anthers 4–5 mm long, completely exserted or basal part (ca 1 mm long) included in corolla tube at anthesis; filaments 0.5–1 mm long. Ovary 1.5–2 mm long, densely covered with long, erect or spreading hairs; per locule (1–)4–8 ovules arranged at periphery of placenta attached to upper half of septum. Style and stigma 10–15 mm long, exserted for 5–7 mm; style densely covered with long upwardly directed hairs from ca 3 mm above base to just below papillate zone; stigmatic lobes 6–7 mm long, upper part fusiform; papillae absent along fusiform part, present lower down in longitudinal grooves. Fruits spherical, 5–7 mm in diameter, faintly ridged longitudinally and glossy when dried, densely covered with ± long erect hairs; fruit wall thin, with sclerified vascular bundles; pyrenes hemi-ovoid, ca 6 × 4 mm, membranous adaxially, crustaceous abaxially, with rounded tip and base, small adaxial opening somewhat above the middle and faint longitudinal central ridge running from the apex to the top of the adaxial opening and continuing into a longitudinal depression below it. Seeds (2–)4–8 per fruit, 2–4 × 1.5–3 mm.
Distribution
Restricted to southern Madagascar from Ihosy in the north and east to Toliara in the west and Beraketa in the south. Present in: Ihosy District, Ihorombe Region (Fianarantsoa Province); Bekily District, Androy Region, Betroka District, Anosy Region, and, Sakaraha and Toliary II Districts, Atsimo-Andrefana Region (Toliara Province) (Fig. 23C).
Habitat and phenology
Deciduous and semi-deciduous dry forest; on sandy soil or rocky substrate; elev. 550–1250 m. Flowers: December–January, one collection reported flowering in April (Seyrig 425B); Fruits: February–May.
Vernacular uses
Edible fruits (Homolle 1610); vermifuge (Homolle 1610).
Provisional IUCN assessment
Vulnerable: VU B2ab(iii). This assessment is based on 15 collections with detailed locality data, collected between 1943 and 2007. The EOO of P. seyrigii sp. nov. is estimated to be 24 441 km 2, exceeding the upper limit of the Vulnerable category under criterion B1. The AOO is 44 km 2, which complies with the Endangered category under criterion B2. The species occurs in 8 locations, which complies with the Vulnerable category under subcriterion ‘a’ of criterion B2. Paracephaelis seyrigii sp. nov. is present in the Isalo and Zombitse-Vohibasia National Parks. Both parks are threatened by yearly bushfires, penetrating forested or woody areas, resulting in an impoverishment of the natural vegetation and limited regeneration. Local populations enter the parks to extract construction and firewood. Charcoal is illegally produced in Zombitse. Areas are deforested for subsistence agriculture. Hunting and gathering of nontimber forest products, e.g., honey, is common (BirdLife International 2020d, 2020e; Nicoll & Langrand 1989). Sapphire mining is becoming a problem in Isalo (BirdLife International 2020e). These threats are even more important outside the protected areas. Therefore, a reduction in the extent and quality of the habitat of P. seyrigii sp. nov. is inferred. This fact, in combination with the low AOO and the low number of locations, qualifies the species for Vulnerable status.
Notes
1. Paracephaelis seyrigii sp. nov. is similar to P. saxatilis but more robust in most of its characters: e.g., larger leaves, longer petioles, larger inflorescences, longer calyx lobes. The distribution of the two species does not overlap. The distribution area of P. seyrigii sp. nov. lies to the west and north of that of P. saxatilis.
2. Leroy distinguished P. seyrigii sp. nov. as a distinct species of Paracephaelis under the name “ Paracephaelis recurva ”. He annotated several specimens in the P herbarium, e.g., Seyrig 425 and 425B, Homolle 1610, Humbert 28670, coll. ignot. 6439 and 5765, but never formally published the name.
description: Published as part of Block, Petra De, 2022, Monograph of the western Indian Ocean genus Paracephaelis (Rubiaceae - Pavetteae), with description of thirteen new species, pp. 1-99 in European Journal of Taxonomy 801 on pages 77-80, DOI: 10.5852/ejt.2022.801.1685, http://zenodo.org/record/6358810