Astiella pulla Groeninckx & Janssens & Smets & Verstraete 2017, sp. nov.
Creators: name: Groeninckx, Inge
name: Janssens, Steven
name: Smets, Erik
name: Verstraete, Brecht
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Gentianales
Rubiaceae
Astiella
Astiella pulla

description: Astiella pulla Groeninckx sp. nov.
http://www.ipni.org/urn:lsid:ipni.org:names:77161727-1
Figs 2K, 15
Diagnosis
Astiella pulla sp. nov. resembles A. antsalovansis sp. nov. in having black seeds with a reticulate seed coat surface consisting of 5- to 6-angular testa cells and in having a ring of trichomes inside the corolla tube, but differs in having more robust inflorescence axes (vs slender), 4 to 5 ovules per locule (vs 3), a longer style that is always exserted in brevistylous flowers (vs a shorter style that is included), and fruits 1.5–3.4 × 2.6–4 mm (vs 1–2 × 1.5–3 mm).
Etymology
The specific epithet is the feminine form of the Latin adjective ‘ pullus ’ that means ‘dark-coloured’ and refers to the black seeds.
Type
MADAGASCAR: Mahajanga province, Boeny region, Mahajanga I district:ca 20km before Mahajanga, Marohogo, RN 4, just next to road, 47 m, 19 Mar. 2010, Groeninckx, De Block & Rakotonasolo 271 (holo-: BR; iso-: BR, G, K, MO, P, TAN, WAG).
Additional material examined
MADAGASCAR: Mahajanga province, Boeny region, Mahajanga I district, sur le calc rocin à Marohogo près Majunga, s.d., Perrier de la Bâthie 17633 (P).
Description
Annual herb, erect, up to 20 cm tall; stems quadrangular in cross section, glabrous or sometimes scabrate on the ribs. Stipule base 0.2–1 mm long, beset with a few short trichomes; fimbriae 4–9, 0.2–0.8 mm long, sometimes inconspicuous, colleter-tipped. Leaves sessile; blades ovate, elliptic, narrowly ovate or narrowly elliptic, 8–32 × 3–8.5 mm, glabrous, darker green above, paler green below; base attenuate; apex acute; margin revolute when dry, scabrate; midvein prominent below, glabrous or scabrate; secondary veins invisible or 3–4 on each side of the midvein; intersecondaries invisible. Inflorescences terminal or pseudo-axillary, very lax compound and reduced dichasia, 3- to several-flowered; bracts at main branchings leaf-like; peduncle absent; inflorescence branches up to 6 cm long, glabrous or scabrate. Pedicels absent or 0.5–1.5 mm long, glabrous or scabrate. Flowers heterostylous. Calyx green; tube reduced; lobes 4, ovate with acuminate tip, 1–1.7 × 0.7–1 mm, glabrous, margin ciliolate. Corolla white; tube cylindrical 2.2–2.8 × 1–1.5 mm in brevistylous flowers, 1.5–2.2 × 0.8–1.2 mm in longistylous flowers, glabrous outside, with a ring of trichomes in the lower half inside; lobes 4, ovate, 0.6–1.4 × 0.5–1.3 mm, glabrous inside except for trichomes towards the margin. Stamens inserted near the base of the corolla lobes and exserted for 0.6–0.9 mm beyond the corolla throat in brevistylous flowers, inserted in the middle of the corolla tube and included in longistylous flowers. Anthers ellipsoid, 0.5–0.7 mm long; filaments dorsifixed, 0.4–0.5 mm long. Pollen 7-aperturate. Ovary 2-locular, depressed obovoid, 0.5–1 × 0.7–1.3 mm, glabrous to sparsely pubescent; placenta attached near the middle of the septum, stalked, subglobose, bearing 4 to 5 ovules per locule. Style 2.3–3 mm long and exserted for 0.2–0.3 mm beyond the corolla throat in brevistylous flowers, 2.5–2.8 mm long and exserted for 0.6–0.7 mm beyond the corolla throat in longistylous flowers, glabrous; stigma bilobed, lobes 0.5–0.8 mm long, hirtellous. Capsules broadly depressed obovoid, 1.5–3.4 × 2.6–4 mm, crowned with the persistent calyx lobes, glabrous or with a few scabrate trichomes, dehiscence loculicidal. Seeds 1, 3 or 4 per locule, elliptic in outline, ventral groove absent, 0.8–1 × 0.6–0.8 × 0.4–0.5 mm, hilum in the middle, black; seed coat surface reticulate, 5- to 6-angular testa cells, microsculpturing favulariate.
Distribution
NW Madagascar: Mahajanga province, Boeny region, Mahajanga I district.
Habitat
Western (degraded) dry forest; dark clay on calcareous underground; at 47 m elevation.
Conservation status
Known from only one locality. Given its apparent rarity and following the recommendation of Callmander et al. (2005) to avoid the Data Deficient category, we consider the species as vulnerable (VU D2) based on its restricted area of occupancy (D2) and the high human pressure present in the entire area resulting in a general decline of suitable habitats (dry forest) for the species.
description: Published as part of Groeninckx, Inge, Janssens, Steven, Smets, Erik & Verstraete, Brecht, 2017, Description of 11 new Astiella (Spermacoceae, Rubiaceae) species endemic to Madagascar, pp. 1-40 in European Journal of Taxonomy 312 on pages 33-34, DOI: 10.5852/ejt.2017.312, http://zenodo.org/record/3827336