Astiella perrieri 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 : 29-33

Astiella perrieri Groeninckx sp. nov.

http://www.ipni.org/urn:lsid:ipni.org:names:77161726-1

Figs 2J , 5N–O , 11C , 14

Diagnosis

Astiella perrieri sp. nov. resembles A. homolleae sp. nov. in having a reduced corolla tube with the stamens always exserted beyond the corolla throat, but differs in having an annual habit (vs perennial), stipules with less and shorter fimbriae (2–4 fimbriae vs 4–8 and 0.8–2.7 mm vs 1–4 mm long), a glabrous corolla tube on the inside (vs papillate with trichomes towards the base), and seeds elliptic in outline with granulate microsculpturing (vs seeds triangular in outline with a verruculate microsculpturing).

Etymology

The specific epithet is dedicated to the French botanist H. Perrier de la Bâthie who specialized in the plants of Madagascar.

Type

MADAGASCAR: Fianarantsoa province, Horombe region, Ivohibe district, Andringitra, area around campement 1, humid forest, along forest trails and in open places, 28 Jan. 2006, De Block, Tosh & Rakotonasolo 1927 (holo-: BR; iso-: BR, MO, P, TAN).

Additional material examined

MADAGASCAR: Antanarivo province, Analamanga region, Anjozorobe district, Ampilanonana, Ambohitsitakatra, 1300 m, 3 Apr. 1999, Rakotonasolo & Ramaroson 89a ( BR, K); Ampilanonana, Ambohitsitakatra, on rock, 1300 m, 3 Apr. 1999, Rakotonasolo & Ramaroson 90 (K, TAN). Antsiranana province, Melaky region, Besalampy district, Mares de dissolution latéritique, plateau de Marangaka [Mrangaka], 1600 m, Dec. 1912, Perrier de la Bâthie 15163 ( P). Fianarantsoa province, Atsimo- Atsinanana region, Befotaka district, Pce. de Farafangana, bord des routes en forêt humide, 16Aug. 1926, Decary 4431 ( P). Horombe region, Ivohibe district, Massif d’Andringitra, forêt à sous bois herbacé, 1600 m, Feb. 1922, Perrier de la Bâthie 14472 ( P). Mahajanga province, Sofia region, Bealanana district, Montagnes au nord de Mangindrano (haute Maevarano) jusqu’aux sommets d’Ambohimirahavavy (partage des eaux Mahavavy Androranga: centre nord), clairière maricageuse dans la forêt ombrophile sur latérite de gneiss, par petites plaques à la lisière, en prairie secondaire, 1900 m, 19 Jan.–12 Feb. 1951, Humbert & Capuron 24953 ( BR, MO, P, TAN). Toamasina province, Alaotra-Mangoro region, Moramanga district, Beforona [Bé-fouram], s.d., Bojer s.n. (K, P). Anosibe An’Ala district, Terrain humide près d’un forêt, village d’Analamazava [Alamazaze], 1000 m, 13 May 1881, Lantz s.n. ( P). Analanjirofo region, Maroantsetra district, Island of Nosy Mangabe, 5 km S of Maroantsetra in the Bay of Antongil, along north trail, in full shade, 10 m, 26 Apr. 1990, Carlson 179 ( MO, TAN); Nosy Mangabe coastal path from W landing towards N end, bank above path, lowland evergreen rainforest, near Cyperus and Diospyros , on laterite, 10 m, 29 Feb. 1988, Cheek & Schatz 1380 (K); Nosy Mangabe, a 520 ha island in the Bay of Antongil, 5 km from Maroantsetra, 0–330 m, 9 Jan. 1989, Schatz & Miller 2514 ( MO, P, TAN); Nosy Mangabe, a 520 ha island in the Bay of Antongil, 5 km from Maroantsetra, 0–330 m, 4 Dec. 1987, Schatz & Villiers 1833 (K, MO, P, TAN). Locality unknown, Bois humides, rivière Simianona [Simiana], 200 m, Sep. 1912, Perrier de la Bâthie 3958 ( P); Bois, rivière Mananara, 200 m, Oct. 1912, Perrier de la Bâthie 9741 ( P).

Description

Annual herb, creeping, fertile stems 4–20 cm tall, with fine rooting system, rooting at the nodes; stems quadrangular in cross section, only sparsely branching, glabrous or puberulent, green to reddish green. Stipule base 0.5–1.5 mm long, glabrous or pubescent; fimbriae 2–4, 0.8–2.7 mm long, colleter-tipped. Leaves petiolate or sessile; petioles 0.5–3.5 mm long, glabrous; blades broadly elliptic or broadly ovate, more rarely elliptic, 2.2–26.5 × 1.8–14.5 mm, sparsely to densely strigose above particularly towards the edges (but see remarks), glabrous to sparsely puberulent below particularly on the veins, darker green above, paler green below; base attenuate; apex acute; margin ciliolate; midvein prominent particularly below; secondary veins 2–5 at each side of the midvein, prominent below; intersecondaries prominent. Inflorescences terminal or pseudo-axillary, single or compound dichasia, 3- to severalflowered, subtended by one leaf pair; peduncle absent or 5–40 mm long, glabrous; lower bracts leaf-like, upper bracts fimbriate. Pedicels 0.5–16 mm long, glabrous to sparsely puberulent. Flowers heterostylous. Calyx green; tube reduced; lobes 4, triangular to narrowly triangular, 1–1.5 × 0.4–0.6 mm, glabrous or beset with trichomes particularly at the sinuses, colleters in between. Corolla white, pale pink, pale blue or pale purple; tube reduced or cylindrical, 0.6–1.5 mm long (but see remarks), glabrous; lobes 4, elliptic, 1.2–2.7 × 1.1–1.7 mm, glabrous outside, papillate and sparsely beset with trichomes inside. Stamens inserted near the base of the corolla lobes, exserted for 1.5–2.2 mm beyond the corolla throat in brevistylous flowers, exserted for 0.5–1.5 mm beyond the corolla throat in longistylous flowers.Anthers ellipsoid, 0.5–1 mm long, purple or white; filaments dorsifixed, 1.3–2 mm long in brevistylous flowers, 0.4–0.5 mm long in longistylous flowers. Pollen tricolporate, oblate spheroidal, prolate spheroidal or subprolate in brevistylous flowers, prolate spheroidal to subprolate in longistylous flowers; E 16–22 μm in brevistylous flowers, 17–20 μm in longistylous flowers; P 18–26 μm in brevistylous flowers, 21–22 μm in longistylous flowers; ectocolpi long; endocolpi long; tectum bireticulate; suprareticulum microreticulate to reticulate, smooth; infrareticulum perforate to microreticulate with granules and/or spines on the muri in brevistylous flowers, reduced in longistylous flowers to granules and/or spines in the lumina around the edges of the muri. Ovary 2-locular, broadly obovoid to broadly depressed obovoid, 0.5–0.7× 0.6–1.1 mm, glabrous; placenta attached near the middle of the septum, stalked, subglobose, bearing few ovules per locule (but more than 3). Style 1–1.5 mm long and included in brevistylous flowers, 3–6 mm long and exserted for 2.4–5 mm beyond the corolla throat in longistylous flowers, papillate; stigma bilobed, lobes 0.7–0.9 mm long in brevistylous flowers, 0.7–2.3 mm long in longistylous flowers, hirtellous. Capsules broadly obovoid, 1.3–2.7 mm long, 2– 2.8 mm wide, crowned with the persistent calyx lobes, glabrous, green, dehiscence loculicidal. Seeds few per locule, elliptic in outline, ventral groove absent, 0.6–0.7 × ca 0.5 × ca 0.5 mm, black or dark brown; seed coat surface reticulate, testa cells with undulating radial walls, microsculpturing granulate.

Distribution

E Madagascar: Antananarivo province, Analamanga region, Anjozorobe district; Antsiranana province, Melaky region, Besalampy district; Fianarantsoa province, Atsimo-Atsinanana region, Befotaka district; Fianarantsoa province, Horombe region, Ivohibe district; Mahajanga province, Sofia region, Bealanana district; Toamasina province, Alaotra-Mangoro region, Moramanga district; Toamasina province, Analanjirofo region, Maroantsetra district.

Habitat

Humid forest; along forest trails; secondary savannas; laterite substrate; at 0–1900 m elevation.

Conservation status

The species is known from 15 collections, of which two without locality. The number of locations is eight. The extent of occurrence is more than 20,000 km 2; the area of occupancy equals 36 km 2. Throughout the species’ distribution range, there is a high human pressure on the natural habitats. The species is therefore classified as vulnerable: VU B2ab(i,ii,iii).

Remarks

The specimen Lantz s.n. could be included in A. perrieri sp. nov. although it has flowers with welldeveloped corolla tubes (2.3–2.6 mm long). Several other specimens collected on the Island of Nosy Mangabe (Carlson 179, Cheek 1380, Schatz & Miller 2514, Schatz & Villiers 1833) could be included as well, but these can be distinguished from the other A. perrieri specimens by their glabrous leaves. Because of these discrepancies, these specimens were not included in the species description.

Figures

Fig. 2. Distribution maps. A. Astiella antongilensis Groeninckx sp. nov. B. A. antsalovansis Groeninckx sp. nov. C. A. confusa Groeninckx sp. nov. D. A. deblockiae Groeninckx sp. nov. E. A. delicatula Jovet. F. A. desseinii Groeninckx sp. nov. G. A. homolleae Groeninckx sp. nov. H. A. latifolia Groeninckx sp. nov. I. A. longifimbria Groeninckx sp. nov. J. A. perrieri Groeninckx sp. nov. K. A. pulla Groeninckx sp. nov. L. A. tsaratanensis Groeninckx sp. nov.

Fig. 5. Scanning electron microscopy micrographs of seeds and a detail of their surface. A–B. Astiella antsalovansisGroeninckx sp. nov.C–D.A. deblockiaeGroeninckx sp. nov.E–F.A. desseiniiGroeninckx sp. nov. G–I. A. delicatula Jovet. J–K. A. homolleae Groeninckx sp. nov. L–M. A. latifolia Groeninckx sp. nov. N–O. A. perrieri Groeninckx sp. nov. P–R. A. tsaratanensis Groeninckx sp. nov. Scale bars for A, C, E, J, L, N = 100 µm; B, I = 50 µm; D = 10 µm; F, K, M, O, R = 20 µm; G, H, P, Q = 200 µm.

Fig. 11. Scanning electron microscopy micrographs of pollen in polar view (PV), the apocolpium (AC), pollen in equatorial view (EV) and the mesocolpium (ME). A. Astiella homolleae Groeninckx sp. nov. B. A. latifolia Groeninckx sp. nov. C. A. perrieri Groeninckx sp. nov. D. A. tsaratanensis Groeninckx sp. nov. Scale bars for A: PV = 2 µm, AC, ME = 1 µm, EV = 5 µm; for B and C: PV, EV = 5 µm, AC, ME = 1 µm; for D: PV, EV = 5 µm, AC = 2 µm, ME = 1 µm.

Fig. 14. Astiella perrieri Groeninckx sp. nov. A. Habit. B. Brevistylous flower. C. Open brevistylous flower. D. Open longistylous flower. E. Ovary dissected to show placentation; all ovules removed from the right locule to show the placenta. F. Capsule. Drawn by Marijke Meersman. A–C, E from De Block, Tosh & Rakotonasolo 1927 (BR); D from Perrier de la Bâthie 3958 (P); F from Perrier de la Bâthie 14472 (P).