Tulearia De Block, 2018

Block, Petra De, Rakotonasolo, Franck, Ntore, Salvator, Sylvain G. Razafimandimbison, & Janssens, Steven, 2018, Four new endemic genera of Rubiaceae (Pavetteae) from Madagascar represent multiple radiations into drylands, PhytoKeys 99, pp. 1-66 : 1

Tulearia De Block gen. nov.

Diagnosis.

Differing from Paracephaelis sericea by the presence of shoot dimorphism, the smaller leaves grouped terminally on lateral short-shoots (blades ≤ 3.5 × 1.5 cm vs. 7-21 × 4.5-12 cm in P. sericea ), the uni- or pauciflorous inflorescences (1-5 vs. 15 to numerous flowers), the trilobate bracts and bracteoles (vs. triangular), the variability in the number of calyx lobes [(4-)5-7 vs. 5], the pollen without supratectal elements (vs. supratectal elements present) and the fruit with 2 ruminate seeds (vs. 4-10 seeds with entire endosperm).

Type species.

Tulearia splendida De Block.

Shrubs; shoot dimorphism present: vegetative long-shoots with well-developed internodes, reproductive short-shoots with compressed internodes and densely beset with corky stipular remnants; vegetative parts densely pubescent. Leaves grouped terminally on short-shoots, persistent, petiolate with petioles short and canaliculate above; blades <4 × 1.5 cm, coriaceous; domatia absent; margins strongly revolute. Stipules triangular with short acuminate tip, inside densely covered with appressed hairs all over (hairs visible along the margins from the outside) and with large colleters in the lower half. Inflorescences terminal, sessile, uni- or pauciflorous, cymose with trichotomous branching; all parts (axes, bracts, bracteoles, pedicels) densely pubescent; bracts and bracteoles trilobate. Flowers hermaphroditic, pentamerous, shortly pedicellate; all parts (ovary, calyx, corolla) densely pubescent outside; secondary pollen presentation present. Calyx well-developed, either with short tube and long lobes or with lobes as long as or shorter than tube; lobes (4-)5-7(-8). Corolla white, sericeous outside; tube narrowly cylindrical; lobes contorted to the left in bud and spreading at anthesis. Stamens inserted in the sinuses of the corolla lobes at or somewhat below the level of the throat; filaments short; anthers usually partly included in the corolla tube at anthesis, basifixed, with sagittate base and short sterile apical appendix. Disc annular, fleshy, glabrous. Ovary cup-shaped, bilocular or rarely trilocular; placentation axile, with 3-7 ovules arranged along the periphery of a small placenta attached to the upper half of the septum. Style and stigma white, exserted from the corolla tube at anthesis; stigmatic lobes fused over their entire length except for the very tips, receptive zone on the adaxial surfaces of the free tips and along the lines of fusion of the lobes. Fruits drupaceous, subspherical, pubescent, crowned by the persistent calyx, containing 2 pyrenes; pyrenes crustaceous or stony, hemi-ovoid, formed by the convex outer and flat inner parts of each locule, with central apical protuberance or ridge on the adaxial side, opening along a central longitudinal preformed germination slit present over the entire length on the abaxial and adaxial sides (running through apical ridge or apical protuberance), containing 1 or very rarely 2 seeds; seed hemi-ovoid (or angular in case of 2 seeds per pyrene); hilum ovate, superficial, annulus around hilum absent; exotesta cells parenchymatic and filled with tannins; endotesta consisting of crushed cell layers without crystals; endosperm ruminate. Pollen grains 3-zonocolporate, exine microreticulate to perforate, supratectal elements absent.

A genus of two species, restricted to the dry forest and scrub of southern and southwestern Madagascar, on calcareous soil.

Etymology.

The genus is named for its occurrence in the region of Toliara ( Tuléar).

Key to the species of Tulearia

1	Leaves 10-35 × 6-15 mm, secondary nerves visible; inflorescences with (1-)3(-5) flowers; bracteoles 8-12 mm long; calyx lobes 7.5-10 mm long; calyx tube much shorter than lobes	T. splendida
-	Leaves 5-20 × 3-5.5 mm; secondary nerves not visible; inflorescences uniflorous; bracteoles ≤ 3.5 mm long; calyx lobes 1-2 mm long; calyx tube as long as or longer than lobes	T. capsaintemariensis