Monodora hastipetala Couvreur, 2006

Couvreur, Thomas L. P., Gereau, Roy E., Wieringa, Jan J. & Richardson, James E., 2006, Description of four new species of Monodora and Isolona (Annonaceae) from Tanzania and an overview of Tanzanian Annonaceae diversity, Adansonia (3) 28 (2), pp. 243-266 : 250-253

Monodora hastipetala Couvreur , sp. nov.

( Fig. 3 )

Haec species inter congeneros quoad folia glabra ad basin rotundata cuneatave, flores solitarios, petala externa elliptica usque ovata margine undulata etiam interna ungue longiore quam latiore ad Monodoram angolensem Welw. maxime accedit, sed ab ea petalis internis hastatis lamina longiacuminata intus ad basin dense pubescente trichomatibus c. 1 mm longis distinguitur.

TYPUS. — Tanzania. Pwani Region, Rufiji Distr., Matumbi Hills, Kiwengoma Forest , 19.X.1997, fl., 08°19’01”S, 38°57’07”E, Phillipson 4958 (holo-, MO!) .

OTHER MATERIAL EXAMINED. — Tanzania. Pwani (Coast) Region, Rufiji Distr., northern edge of the Matumbi Highlands , Kiwengoma Forest , 8°21’S, 38°51’E, alt. 365 m, 20.XI.1989, fl., Frontier-Tanzania 22 (C!, MO!). — Matumbi Hills, Kiwengoma Forest , 8°19.0’S, 38°57.1’E, 8.VI.1997, fr., P. B. Phillipson 4803 (MO!) .

HABITAT. — Dry scrub and riverine coastal forest, at 225-365 m altitude.

DISTRIBUTION. — Only known from the Kiwengoma forest (Matumbi Hills) in Tanzania ( Fig. 5 ).

DESCRIPTION

Tree to 8 m tall; bark grey with white lenticels; young branchlets drying black, glabrous. Petiole c. 2 mm long, glabrous, with a groove above; leaf blade spatulate to narrowly obovate, sometimes narrowly elliptic, papyraceous, 10-12 × 3-4 cm, acuminate at apex, cuneate to rounded at base, glabrous; midrib prominent below, raised above; secondary veins 10 to 14 pairs, strongly curved, anastomosing c. 4 mm from margin; tertiary veins intermediate between percurrent and reticulate.

Flowers solitary and axillary, pendulous, flowering on new branches; pedicel slender, in flower 17- 20 mm long, in fruit c. 20 mm long, robust, glabrous; bract inserted in upper half of pedicel, rounded, cup-shaped, 5-9 × 3-5 mm, auriculate-clasping, pale green, glabrous, the margins non-undulate. Sepals elliptic, 6-7 × 3-4 mm, rounded at apex, glabrous, the margins entire; outer petals held horizontally when fully opened, narrowly elliptic, 20-26 × 6- 8 mm, cuneate at apex, undulate, glabrous, white; inner petals clawed, white to pale green, tinged purple, the claw 4-5 mm long, c. 1 mm wide, the lamina narrowly ovate, 10-17 × 4-7 mm, connivent by the center over receptacle, long-cuneate at apex, densely pubescent with trichomes c. 1 mm long inside at base, less pubescent on outer side; stamens 40 to 50, c. 0.6 mm long, glabrous, the connective appendages c. 0.1 mm long; ovary c. 1 mm long with a glabrous stigma.

Fruit nearly ovoid, 30 mm long, c. 20 mm in diam., bumpy and irregularly ribbed when dried; seeds c. 10 mm long, c. 7 mm wide, smooth, light brown.

Pollen: tetrad acalymmate, tetragonal sub-square shaped, monads coherent.Size at longest axis:Tetrad: 50-57 µm; monad: 21-33 µm. Tectum structure: smooth, rugulate-perforate. Perforations rounded to oval> 0.2 µm. More coarsely rugulate than in M. carolinae ( Fig. 7E, F ).

VERNACULAR NAME

Nnjende (Kimatumbi).

NOTES

This species has a very restricted distribution and has characteristic flowers.

Figures

FIG. 3. — Monodora hastipetala Couvreur: A, flowering branch; B, mature flower (top view), outer petals opened; C, pedicel with sepals; D, androecium and gynoecium; E, stamen; F, fruiting pedicel and fruit. Drawing by Wil Wessel-Brand. Scale bars: A-C, F, 1 cm; D, E, 1 mm.

FIG. 5. — Distribution of the new species of Monodora in Tanzania and Mozambique. Symbols: grey patches, land above 1400 m; ■, M. carolinae Couvreur;●, M. globiflora Couvreur;▲, M. hastipetala Couvreur.

FIG. 7. — SEM of pollen grains and tectum structure: A, B, Monodora carolinae Couvreur; C, D, M. globiflora Couvreur; E, F, M. hastipetala Couvreur; G, H, Isolona hexaloba Engl. & Diels from Ivory Coast; I, J, Isolona linearis Couvreur. A, B, Phillipson 4940 (C); C, D, Luke 3136 (MO); E, F, Phillipson 4958 (MO); G, H, de Wilde et al. 839 (WALKB, WAG); I, J, Frimodt-Møller et al. TZ59 (C). Scale bars: A, C, E, G, I, 10 µm; B, D, F, H, J, 1 µm.