Astiella antongilensis Groeninckx, 2017

Groeninckx, Inge, Janssens, Steven, Smets, Erik & Verstraete, Brecht, 2017, Description of 11 new Astiella (Spermacoceae, Rubiaceae) species endemic to Madagascar, European Journal of Taxonomy 312, pp. 1-40 : 4-7

publication ID	https://doi.org/ 10.5852/ejt.2017.312
DOI	https://doi.org/10.5281/zenodo.3846886
persistent identifier	https://treatment.plazi.org/id/039E3C56-5A2E-FF84-9D5B-00D0E18C0B89
treatment provided by	Carolina
scientific name	Astiella antongilensis Groeninckx
status	sp. nov.

Treatment

Astiella antongilensis Groeninckx View in CoL sp. nov.

http://www.ipni.org/urn:lsid:ipni.org:names:77161710-1

Figs 1 View Fig , 2A View Fig

Diagnosis

Astiella antongilensis sp. nov. resembles A. homolleae sp. nov. and A. perrieri sp. nov. in having a reduced corolla tube and numerous ovules per locule, but differs in having a pubescent stem, large leaves that are covered with trichomes below, and pubescent flowers.

Etymology

The epithet refers to Antongil Bay, the largest bay in Madagascar and the area where the species is found.

Type

MADAGASCAR: Toamasina province, Analanjirofo region, Maroantsetra district. Côte est, environs de la baie d’Antongil, bois, 200 m, Oct. 1912, Perrier de la Bâthie 3749 (holo-: P, P 00219825; iso-: P, P 00516317).

Description

Annual herb, ca 10 cm tall; stems quadrangular in cross section, pubescent. Stipule base 1–2 mm long, pubescent; fimbriae 3–6, 1– 2 mm long, colleter-tipped. Leaves petiolate; petiole 5–15 mm long, pubescent; blades elliptic, slightly ovate or obovate, (12–)45–72 × (6–) 10–26 mm, very sparsely covered with trichomes particularly on the veins above, more densely covered with trichomes below; base attenuate; apex acute or obtuse; margin ciliolate; midvein prominent particularly below; secondary veins 4–7 on each side of the midvein; intersecondaries invisible. Inflorescences terminal, multi-flowered; peduncle 0–40 mm long, pubescent. Pedicels 1–7 mm long, pubescent. Flowers heterostylous (but both style and anthers exserted). Calyx green; tube reduced; lobes 4, narrowly triangular or triangular, 1–1.3 × 0.4–0.5 mm, pubescent. Corolla white or pale purple; tube reduced, 0.2–0.5 mm long; lobes 4, somewhat spathulate, 2.1–2.8 mm long, 0.5–0.6 mm wide at the base, 1–1.2 mm wide at the top, pubescent outside, papillate inside. Stamens inserted near the base of the corolla lobes and exserted for 2.2–3.2 mm beyond the corolla throat. Anthers ellipsoid, 1.2–1.4 mm long; filaments dorsifixed, ca 3.3 mm long in brevistylous flowers, ca 1.2 mm long in longistylous flowers. Pollen unknown. Ovary 2-locular, broadly obovoid, 1–1.2 × 1–1.3 mm, densely pubescent; placenta attached above the middle of the septum, stalked, elongated, bearing numerous ovules per locule. Style ca 3.3 mm long in longistylous flowers (exserted for ca 3 mm beyond the corolla throat), ca 2.5 mm long in brevistylous flowers (exserted for ca 2.2 mm beyond the corolla throat), glabrous; stigma bilobed, lobes 0.6–1 mm long, papillate. Capsules broadly obovoid or broadly depressed obovoid, 2.5–3 × 2.5–3 mm, crowned with the persistent calyx lobes, pubescent, dehiscence loculicidal. Seeds unknown.

Distribution

E Madagascar: Toamasina province, Analanjirofo region, Maroantsetra district.

Habitat

Humid forest; at 200 m elevation.

Conservation status

The species is only known from its type collected in 1912. There is no detailed information about the locality where the specimen was collected. 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 (humid forest) for the species.