Astiella Jovet ( Jovet 1941 )

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 : 2-4

Astiella Jovet ( Jovet 1941)

Etymology

Jovet, the author of the genus Astiella , dedicated the genus name to his wife Suzanne Jovet-Ast.

Type species

Astiella delicatula Jovet.

Description

Annual or perennial herb, prostrate or erect, 4–60 cm tall, sometimes rooting at the nodes; stems quadrangular, glabrous or variously covered with trichomes. Stipules glabrous or pubescent; fimbriae 0–9, 0.1–6.5 mm long, often colleter-tipped. Leaves sessile or petiolate, sometimes anisophyllous, sometimes succulent; petioles 0.4–17 mm long; blades mostly narrowly elliptic to broadly ovate, rarely linear, 2.2–92 × 0.5–30.5 mm, glabrous or covered with trichomes, often darker green above, paler green below; base attenuate; apex acuminate, acute or obtuse; margin sometimes revolute when dry, scabrate or ciliolate, rarely glabrous; midvein prominent particularly below; secondary veins prominent or invisible; intersecondaries mostly invisible, sometimes prominent. Inflorescences terminal or pseudo-axillary, single or compound dichasia, 1- to multi-flowered; peduncle 0–56 mm long, glabrous to pubescent. Pedicels absent or 0.2–16 mm long, glabrous or pubescent. Flowers predominantly heterostylous, rarely isostylous. Calyx green; tube reduced; lobes 2 or 4, narrowly ovate to broadly ovate or narrowly triangular to triangular, glabrous to densely pubescent, sometimes colleters in between. Corolla mostly white, sometimes pale pink, pale purple or pale blue; tube cylindrical or funnel-shaped, glabrous or pubescent; lobes 4, mostly narrowly ovate to broadly ovate, sometimes elliptic, ligulate or spatulate, glabrous to pubescent. Stamens inserted near the base of the corolla lobes or in the lower half of the corolla tube, included or exserted. Anthers ellipsoid, rarely broadly obovoid, 0.4–1.8 mm long; filaments dorsifixed, 0.2–3.3 mm long. Pollen tri- or pluricolporate, tectum predominantly bireticulate or rarely aperforate. Ovary 2-locular, mostly broadly obovoid to broadly depressed obovoid, sometimes depressed obovoid, broadly obpyramidal or ovoid, glabrous to pubescent; placenta attached near the middle of the septum, predominantly stalked, globose or elongated, bearing 1 to numerous ovules per locule. Style 0.4–6.5 mm long, included or exserted, mostly glabrous, sometimes hirtellous or papillate; stigma bilobed, lobes 0.1–2.3 mm long, papillate or hirtellous; nectary disc bipartite. Capsules mostly broadly depressed obovoid, sometimes ovoid, rarely broadly obovoid or subglobose, crowned with the persistent calyx lobes, dehiscence loculicidal. Seeds 1 to numerous per locule, mostly elliptic, rarely ovate or triangular in outline, sometimes dorsiventrally flattened, ventral groove present or absent, black or brown; seed coat surface reticulate or rarely alveolate, testa cells with undulating or straight radial walls, microsculpturing favulariate, granulate, rugulose or verruculate; endosperm sometimes ruminate.

Distribution

Distributed throughout Madagascar.

Habitat

Dry forest, humid and sub-humid forest, dunes, savannas, degraded vegetation; calcareous, rocky, laterite, granite or white sand substrate.

Key to the Astiella species

1. Leaf blades 2.2–4.5 × 1.1–2.4 mm ............................................. A. deblockiae Groeninckx sp. nov.

– Leaf blades larger .............................................................................................................................. 2

2. Leaf blades linear or narrowly elliptic; secondary veins obscure or invisible .................................. 3

– Leaf blades different; if narrowly elliptic then secondary veins clearly visible, at least below ....... 4

3. Leaf blades linear, 0.7–1.5 mm wide; flowers sessile ..................... A. desseinii Groeninckx sp. nov.

– Narrowly elliptic, 0.5–4.2 mm wide; flowers pedicellate ............... A. confusa Groeninckx sp. nov.

4. Calyx lobes 2 ........................................................................................................ A. delicatula Jovet

– Calyx lobes 4 .................................................................................................................................... 5 5. Herbs creeping or prostrate, rarely scrambling, rooting at the nodes ............................................... 6

– Herbs more or less erect, not or only rooting at the basal nodes ...................................................... 8

6. Anisophyllous; flowers sessile ......................................................... A. latifolia Groeninckx sp. nov.

– Isophyllous; flowers pedicellate (pedicel sometimes short) ............................................................. 7

7. Corolla tube usually shorter than the corolla lobes; seeds without ventral groove ............................ ........................................................................................................... A. perrieri Groeninckx sp. nov.

– Corolla tube longer than the corolla lobes; seeds with ventral groove ............................................... ................................................................................................. A. tsaratanensis Groeninckx sp. nov.

8. Corolla tube reduced, clearly shorter than corolla lobes .................................................................. 9

– Corolla tube as long or longer than corolla lobes ........................................................................... 10

9. Stems pubescent; leaves covered with trichomes below ........ A. antongilensis Groeninckx sp. nov.

– Stems glabrous or rarely with a few scattered trichomes; leaves glabrous ........................................ ...................................................................................................... A. homolleae Groeninckx sp. nov.

10. Stems glabrous or scabrate at the nodes; stipular fimbriae less than 1 mm long .............................11

– Stems covered with long reddish brown multicellular trichomes; stipular fimbriae 4–6.5 mm long .......................................................................................... A. longifimbria Groeninckx sp. nov.

11. Inflorescence axes slender; 3 ovules per locule; fruits 1–2 × 1.5–3 mm ........................................... ................................................................................................. A. antsalovansis Groeninckx sp. nov.

– Inflorescence axes more robust; 4–5 ovules per locule; fruits 1.5–3.4 × 2.6–4 mm ........................ .............................................................................................................. A. pulla Groeninckx sp. nov.