Pseudocoptosperma De Block

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

publication ID

http://dx.doi.org/10.3897/phytokeys.99.23713

persistent identifier

http://treatment.plazi.org/id/FA27FAAC-6394-C2B3-0D3E-8E6785AE98DA

treatment provided by

PhytoKeys by Pensoft

scientific name

Pseudocoptosperma De Block
status

gen. nov.

Pseudocoptosperma De Block  LSID  gen. nov.

Diagnosis.

Differing from species within the Coptosperma  assemblage by the combination of the following characters: 3 ovules pendulous from a small placenta attached to the upper half of the septum and keeled triangular stipules with well-developed awn (vs. stipules not keeled and without awn, of the "bec du canard" type).

Type species.

Pseudocoptosperma menabense  Capuron ex De Block

Shrubs; vegetative parts except for young shoots glabrous. Leaves persistent, petiolate with petioles short and canaliculate above; blades coriaceous; domatia absent; margins revolute. Stipules triangular with well-developed awns, keeled, with 2 or 3 rows of colleters at the base but otherwise glabrous on the inner surface. Inflorescences terminal, sessile, multiflorous, cymose with trichotomous branching; partial inflorescences compact; all parts (axes, bracts, bracteoles, pedicels) densely pubescent; bracts and bracteoles small, triangular. Flowers hermaphroditic, pentamerous, sessile to shortly pedicellate; all parts (ovary, calyx, corolla) glabrous outside; secondary pollen presentation present. Calyx with short tube and small lobes. Corolla white, turning yellowish with age; tube narrowly cylindrical, short; lobes contorted to the left in bud and spreading at anthesis. Stamens inserted in the sinuses of the corolla lobes at the level of the throat; filaments short; anthers completely exserted from corolla tube at anthesis, basifixed, with sagittate base and short sterile apical appendix. Disc annular, fleshy, glabrous. Ovary cup-shaped, bilocular; placentation axile, with 3 ovules pendulous from the base and the lateral sides of a small placenta attached to the upper half of the septum. Style and stigma exserted from the corolla tube at anthesis; stigmatic lobes fused over their entire length, receptive zone along the lines of fusion of the lobes. Fruits drupaceous, spherical, glabrous, crowned by the persistent calyx, containing 1 pyrene; pyrene crustaceous, spherical, formed by the outer convex parts of one developed and one aborted locule (the septum remaining membraneous and pushed to the side by the developing seed), with a small central apical protuberance on the adaxial side, opening along the line of fusion of the locules, containing 1 seed; seed subspherical; hilum superficial, ovate, 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 with a single species, endemic to western Madagascar.

Etymology.

The genus is named for its resemblance to Coptosperma  .