Isolona thonneri Engl. &amp; Diels, Monogr. Afr. Pflanzenfam. 6: 83 1901
Creators: name: Couvreur, Thomas L. P.
name: Dagallier, Leo-Paul M. J.
name: Crozier, Francoise
name: Ghogue, Jean-Paul
name: Hoekstra, Paul H.
name: Kamdem, Narcisse G.
name: Johnson, David M.
name: Murray, Nancy A.
name: Sonke, Bonaventure
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Magnoliales
Annonaceae
Isolona
Isolona thonneri

description: Isolona thonneri (De Wild. &amp; T. Durand) Engl. &amp; Diels, Monogr. Afr. Pflanzenfam. 6: 83, 1901 Fig. 40; Map 5G ≡ Monodora thonneri De Wild. &amp; T. Durand, Bull. Soc. Roy. Bot. Belg., Compt. Rend. 38: 12, 1899. = Diospyros oblongicarpa Gürke, Bot. Jahrb. Syst. 43: 200, 1909. Type. Cameroon. South Region, Bipindi, Zenker G.A. 3471, 1908: holotype B <i>n.v.</i>: isotype: K[K000199009]; US[US03899523]; WU[WU0040298]. Type. Democratic Republic of the Congo. Equateur; Massanga (près de Monveda), <i>Thonner F. 104</i>, 24 Sep 1896: lectotype, designated by Boutique (1951b), p. 263, sheet here designated: BR[BR0000005113330]; isotypes: BR[BR0000005112715, BR0000005113040]. Description. Tree to shrub, 3-10 m tall, d.b.h. up to 25 cm; stilt roots or buttresses absent, trunk not fluted. Indumentum of simple hairs; old leafless branches glabrous, young foliate branches glabrous. Leaves: petiole 3-8 mm long, 1-2 mm in diameter, glabrous, grooved, <b>blade inserted on the side of the petiole</b>; blade 11-20 cm long, 4-7.5 cm wide, elliptic to obovate, apex acuminate, acumen 1-2 cm long, base decurrent to cuneate, coriaceous to subcoriaceous, below glabrous when young and old, above glabrous when young and old, concolorous; midrib raised above, above glabrous when young and old, below glabrous when young and old; secondary veins 9 to 12 pairs, glabrous below; tertiary venation reticulate. Individuals bisexual; inflorescences ramiflorous on old or young foliate branches, axillary. Flowers with 9 perianth parts in 2 whorls, 1 to 2 per inflorescence; pedicel 5-18 mm long, ca. 1 mm in diameter, glabrous; in fruit 8-10 mm long, 3-4 mm in diameter, glabrous; bracts 3 to 7, several basal and one upper towards the lower half of pedicel, basal bracts ca. 1 mm long, ca. 1 mm wide; upper bracts ca. 2 mm long, 1 mm wide; sepals 3, valvate, free, 2-3 mm long, 1-2 mm wide, ovate, apex acute, base truncate, dark green, glabrous outside, glabrous inside, <b>margins flat</b>; petals basally fused, tube 3-6 mm long, inner and outer whorl not differentiated, equal; <b>lobes 14-31 mm long, 3-5 mm wide, linear to lorate (strap-shaped)</b>, apex acute, green, margins flat, glabrous outside, glabrous inside, pendulous; stamens numerous, in 3 to 4 rows, ca. 2 mm long, broad; connective discoid, glabrous; staminodes absent; carpels fused into a single structure, ca. 2 mm long, stigma bilobed, slightly capitate, sparsely pubescent. Fruit syncarpous, sessile, 40-60 mm long, 20-35 mm in diameter, ellipsoid, apex rounded, <b>glabrous, smooth, not or faintly ribbed</b>, color unknown; seeds not counted, 15-18 mm long, 8-9 mm in diameter, ellipsoid; aril absent. Distribution. A central African species, known from Cameroon to Gabon and the Democratic Republic of Congo; in Cameroon known from the South and East regions. Habitat. An infrequent species; in lowland rain forests, near rivers and swamps. Altitude 450-750 m. a.s.l. Local and common names known in Cameroon. None recorded. IUCN conservation status. Least Concern (LC) (Cosiaux et al. 2019w). Uses in Cameroon. None reported. Notes. <i>Isolona thonneri</i> is characterized by long, narrowly elliptic to linear and glabrous corolla lobes. In the absence of flowers, it is hard to distinguish from <i>I. dewevrei</i>. Specimens examined. <b>East Region</b>: Près de Banana 10 km ENE de Moloundou, 2.08°N, 15.28°E, <i>17 April 1971</i>, <i>Letouzey R.</i> 10682 (P,WAG,YA); near Ndongo ca 45 km WNW of Moloundou, 2.16°N, 14.83°E, <i>15 March 1973</i>, <i>Letouzey R.</i> 12085 (K,P); Près Ndongo à 45 km WNW de Moloundou, 2.15°N, 14.86°E, <i>16 March 1973</i>, <i>Letouzey R.</i> 12111 (BR,K,P,WAG,YA); près Ndongo à 40 km WNW de Moloundou, 2.15°N, 14.86°E, <i>16 March 1973</i>, <i>Letouzey R.</i> 12115 (BR,K,P,WAG,YA). <b>South Region</b>: Colline Ongongondje près Akonekye 15 km NW d’Ambam, 2.46°N, 11.16°E, <i>23 March 1970</i>, <i>Letouzey R.</i> 10205 (BR,COI,K,P,WAG,YA); Inselberg d’Akookas pres du village d’Akookas 38 km au sud est d’Ebolowa, 2.71°N, 11.27°E, <i>15 March 2001</i>, <i>Parmentier I. 1943</i> (BRLU,WAG); Inselberg d’Akookas pres du village d’Akookas 38 km au sud est d’Ebolowa, 2.71°N, 11.27°E, <i>15 March 2001</i>, <i>Parmentier I. 1961</i> (BRLU,WAG).
description: Published as part of <i>Couvreur, Thomas L. P., Dagallier, Leo-Paul M. J., Crozier, Francoise, Ghogue, Jean-Paul, Hoekstra, Paul H., Kamdem, Narcisse G., Johnson, David M., Murray, Nancy A. &amp; Sonke, Bonaventure, 2022, Flora of Cameroon - Annonaceae Vol 45, pp. 1-532 in PhytoKeys 207</i> on pages 149-151, DOI: 10.3897/phytokeys.207.61432
description: {"references": ["Boutique, R, 1951b. Fam. 35. Annonaceae. In: Boutique R (Ed.) Flore du Congo-Belge et du Ruanda-Urundi. I.N.E.A.C., Brussels. https://doi.org/10.2307/3666813", "Le Thomas, A, 1969b. Annonacees. In: Aubreville, A, Ed., Flore du Gabon. Museum National d'Histoire Naturelle, Paris: 1 - 371", "Cosiaux, A, Couvreur, TLP, Erkens, RHJ, 2019w. Isolona thonneri. The IUCN Red List of Threatened Species: e.T132677147A132678239. https://doi.org/10.2305/IUCN.UK.2019-3.RLTS.T132677147A132678239.en"]}