Astiella deblockiae 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 deblockiae

description: Astiella deblockiae Groeninckx sp. nov.
http://www.ipni.org/urn:lsid:ipni.org:names:77161717-1
Figs 2D, 4B, 5 C–D, 7
Diagnosis
Astiella deblockiae sp. nov. resembles A. desseinii sp. nov. and A. latifolia sp. nov. in having tricolporate pollen and numerous ovules per locule, but differs in having a small habit (5 cm vs 10–25 cm tall), very small leaves (2.2–4.5 mm vs 3.2–20(–30) mm long), small corolla tubes (1.5–2.2 mm vs 3.5–11 mm long), small capsules (1.4–2 mm vs 3–4.5 mm long), and dorsiventrally flattened seeds (vs not flattened).
Etymology
The species is named in honour of Dr. Petra De Block, who collected it at the Baies de Sakalaves and who played an important role in making the inventory of Madagascan Rubiaceae.
Type
MADAGASCAR: Antsiranana province, Diana region, Antsiranana I district, Baies de Sakalaves, dunes not far from the beach, low herbaceous vegetation, white sand, 19 Jan. 2002, De Block, Rakotonasolo & Randriamboavonjy 1303 (holo-: BR; iso-: BR, K, MO, P, TAN).
Additional material examined
MADAGASCAR: Antsiranana province, Diana region, Antsiranana I district, Diégo-Suarez, Orangea, en coussinets sur le sable, bord de la mer, 16 Apr. 1970, Bosser 20203 (P); Sud de la forêt d’Orangea, environs de Diégo-Suarez, 24 Nov. 1970, Keraudren-Aymonin & Aymonin 25500 (P).
Description
Perennial herb, prostrate, ca 5 cm tall, somewhat succulent; stems quadrangular in cross section, somewhat lignified at the base, glabrous or scabrate, brown. Stipule base 0.4–0.8 mm long, beset with a few trichomes; fimbriae 2–4, 0.1–0.7 mm long. Leaves petiolate, succulent; petioles 0.4–1 mm long, ciliate; blades ovate, broadly ovate or elliptic, 2.2–4.5 × 1.1–2.4 mm, glabrous except for ciliate margin at the base of the leaf; base attenuate; apex shortly acuminate or acute; margin revolute when dry; midvein prominent below; secondary veins invisible; intersecondaries invisible. Inflorescences pseudo-axillary, mostly 1- to 3-flowered; peduncle absent. Pedicels 1–11 mm long, glabrous. Flowers heterostylous. Calyx green; tube reduced; lobes 4, ovate to broadly ovate, 0.6–1 × 0.5–1 mm, glabrous, colleters and a few trichomes in between the lobes. Corolla pale pink; tube cylindrical, 1.5–2.2 × 0.6–1.4 mm in brevistylous flowers, 0.8–1 × 1.2 mm in longistylous flowers, glabrous outside, with a ring of trichomes (ca 0.3 mm long) at the lower half inside; lobes 4, narrowly ovate or ovate, 1.4–2.5 × 0.7–1 mm, glabrous outside, papillose inside, with a ring of spreading trichomes (ca 0.5 mm long) at the base inside in longistylous flowers. Stamens inserted near the base of the corolla lobes, exserted for 1–1.8 mm beyond the corolla throat in brevistylous flowers, exserted for 0.4–0.6 mm beyond the corolla throat in longistylous flowers. Anthers ellipsoid, 0.7–0.8 mm long; filaments dorsifixed, ca 1 mm long in brevistylous flowers, ca 0.2 mm long in longistylous flowers. Pollen tricolporate, oblate spheroidal to prolate spheroidal; E 24–26 μm; P 23–25 μm; ectocolpi long; endocolpi unknown; tectum bireticulate; suprareticulum microreticulate to reticulate; infrareticulum present as granules in the lumina of the suprareticulum. Ovary 2-locular, broadly obovoid to broadly depressed obovoid, 0.7–1.2 × 0.8–1.5 mm, glabrous to sparsely pubescent; placenta attached near the middle of the septum, stalked, globose, bearing numerous ovules per locule. Style ca 1.5 mm long and included or only with the stigma tips exserted beyond the corolla throat in brevistylous flowers, 2–3.5 mm long and exserted for 1.3–1.7 mm beyond the corolla throat in longistylous flowers, hirtellous; stigma bilobed, lobes ca 0.5 mm long in brevistylous flowers, 0.3–0.5 mm long in longistylous flowers, papillate. Capsules subglobose, 1.4–2 × 1.8–2 mm, crowned with persistent calyx lobes, glabrous, dehiscence loculicidal. Seeds numerous per locule, ovate in outline, dorsiventrally flattened, ventral groove absent, 0.4–0.5 × 0.2–0.4 mm, brown; seed coat surface reticulate, microsculpturing rugulose.
Distribution
N Madagascar: Antsiranana province, Diana region, Antsiranana I district.
Habitat
Dunes close to the sea; white sand substrate.
Conservation status
The species is known from three collections at two localities representing two different locations. The extent of occurrence could not be calculated because there are only two sets of lat/long coordinates. The area of occupancy is estimated smaller than 10 km 2. The main threat for the species is the high human pressure in some areas where the species occurs. A decline in the extent of occurrence, area of occupancy, and area, extent, and/or quality of habitat is therefore very likely. Therefore the species is considered endangered: EN B1ab(i,ii,iii)+2ab(i,ii,iii).
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 13-16, DOI: 10.5852/ejt.2017.312, http://zenodo.org/record/3827336