Monanthotaxis aquila P.H.Hoekstra, 2016

Hoekstra, Paul H., Wieringa, Jan J. & Chatrou, Lars W., 2016, A nonet of novel species of Monanthotaxis (Annonaceae) from around Africa, PhytoKeys 69, pp. 71-103 : 73

Monanthotaxis aquila P.H.Hoekstra sp. nov. Figs 1 , 2 , Table 1

Type.

IVORY COAST. Sassandra , Dakpadou-Sago, 29 March 1968, C. Geerling 2327 (holotype: WAG [2 sheets, barcodes: WAG0005568!, WAG0005569!]; isotype: BR [BR0000015315335!]) .

Diagnosis.

Vegetatively similar to Monanthotaxis atopostema P.H.Hoekstra from Congo and Monanthotaxis couvreurii P.H.Hoekstra from Cameroon. Differs from the latter species in having staminodes alternating with the stamens, and free stamens. Differs from Monanthotaxis atopostema in having only 2 to 3 ovules per carpel, while the latter taxon has up to 6 seeds per monocarp.

Description.

Liana; young branches reddish brown with very short reddish brown hairs 0.1 mm, old branches dark brown, cylindrical with a few lenticels, glabrescent. Leaves: petioles 4-6 × 0.7-1.1 mm, not grooved, pubescence as branches; lamina 3.5-11.5 × 1.9-4.8 cm, length:width ratio 1.8-2.7, oblong, elliptic to slightly obovate, base cuneate to rounded, apex acute to acuminate, acumen to 1 cm, chartaceous, adaxially glossy dark green, abaxially dark silvery green, adaxially glabrous or midrib with a few short hairs, abaxially glabrescent, midrib of young leaves with short appressed yellowish hairs, venation eucamptodromous, secondary veins 6-8, from base curving upwards, tertiary venation scalariform. Inflorescences ramiflorous, axillary or supra-axillary, composed of a solitary flower or a 2 to 3 flowered rhipidium; sympodial rachis 0.5-2 mm with dense appressed short hairs; flowering pedicels 10-18 × 0.3-0.4 mm, with scattered appressed hairs; lower bracts lanceolate to ovate, 0.6-0.9 × 0.3-0.5 mm, indumentum as sympodial rachis; upper bracts at lower half of pedicel, ovate to lanceolate, 0.4-0.7 × 0.3-0.4 mm; flower buds ovate to triangular. Flowers bisexual; sepals 3, connate at base, 0.6 × 1.2-1.3 mm, broadly ovate, apex obtuse, with appressed yellowish hairs; receptacle flat, 1.6-2.0 mm in diameter; petals yellow, in two whorls of 3, but base of inner petals visible in bud; outer petals, 3.4-4.5 × 2.1-2.8 mm, ovate, outside with scattered yellowish appressed hairs, inside with very short appressed hairs at apex; inner petals 2.3-3.5 × 1.3-1.5 elliptic to slightly rhombic, outside with very short yellowish hairs at the apex and in the centre, inside only with hairs at the apex; stamens 9 in one whorl, free, clavate 0.7-0.8 mm, filaments 0.3-0.4 mm, anther cells lateral, connective slightly papillose, truncate, square from above, staminodes 6 alternating between the stamens, but wantingwhere in front of inner petals 0.3 mm, glabrous; carpels 12-13, 0.9-1.0 × 0.4-0.5 mm, ellipsoid, densely hairy, with 2-3 ovules, lateral, stigma subsessile, globose 0.1 mm, glabrous. Fruits: Unknown.

Distribution.

Ivory Coast, province Sassandra. Figure 2 .

Ecology.

Secondary forest, on sandy soil.

Phenology.

Flowering the end of March.

Conservation status.

Proposed IUCN Red List Category: Critically Endangered (CR): B2ab(iii), only known from the type collection and the forests of that area are under serious threat ( Chatelain et al. 1996).

Etymology.

Aquila is the Latin word for eagle. This species is named after my son Arend, the Dutch word for eagle. Aquila is used here as a noun.

Discussion.

This species belongs to a group of species with bisexual flowers, ovate flower buds and predominantly cauliflorous or ramiflorous inflorescences. Most species of this group have obovate to oblanceolate leaves, whereas this species has oblong to elliptic-oblong leaves, a characteristic shared with Monanthotaxis couvreurii and Monanthotaxis atopostema . For the differences between those species see Table 1 . Monanthotaxis vogelii (Hook. f.) Verdc. is similar to Monanthotaxis aquila , but differs in having obovate to oblanceolate leaves with the secondary veins being straight and only slightly curving upwards near the leaf margin and the petals are shorter. Vegetatively Monanthotaxis mannii (Baill.) Verdc. looks similar to Monanthotaxis aquila , but differs in having the inflorescences on the leafy twigs (vs rami- or cauliflorous), and rounded flower buds (vs ovate).

Figures

Figure 1. Monanthotaxis aquila P. H. Hoekstra. A-H drawn from the type (Geerling & Bokdam 2327). A Leaf B Leaf detail C Inflorescence D Flower. Illustration by M. Spitteler, reproduced from Hawthorne and Jongkind (2006).

Figure 2. Distribution map of Monanthotaxis aquila (blue triangle) and Monanthotaxis atewensis (red square).