Plukenetia

1. PLUKENETIA View in CoL sect. ANGOSTYLIDIUM Müll.Arg. View in CoL , Flora 47: 530. 1864. Angostylidium (Müll.Arg.) Pax & K.Hoffm. in A.Engler (ed.), Pflanzenr. IV, 147, IX (Heft 68): 17. 1919. TYPE: Plukenetia conophora Müll.Arg.

Canopy lianas, stems thick. Leaf venation palmate, primary veins 3. Inflorescences unisexual or functionally unisexual; staminate inflorescences racemose thyrses, staminate flowers 3–7/ node in condensed cymules, sometimes with 1–2 apparently nonfunctional pistillate flowers at basal-most nodes; pistillate inflorescences short racemes, pistillate flowers solitary at 1–2(3) basal-most nodes, axes mostly aborted above (rarely with a few staminate flowers in cymules). Staminate flowers: receptacle subglobose; nectaries numerous interstaminal slender-cylindrical segments; stamens 25–50, densely packed; filaments conical,, 0.5 mm long; pollen P 5 34–38 m m, E 5 41 –46 m m, tectum foveolate. Pistillate flowers: styles 75(–90)% connate into a funnel-shaped column, entire style 4–7.5 mm long. Fruits 4(5)–lobed or subglobose-quadrangular, capsule-like, fleshy, indehiscent, 4.5–7.5 cm in diam. Seeds broadly ovoid or subglobose, 25–29 3 25–27 3 25–28 mm (“extra-large” sensu Cardinal-McTeague et al. 2019a).

The single species in this section is distributed in tropical central and western Africa.

Discussion —Section Angostylidium corresponds to subclade P4 ( Fig. 1 View FIG ) and includes a single species, P. conophora , from tropical central and western Africa. This Old World species/ section is morphologically similar to sect. Plukenetia of the Neotropics. Both sections have staminate flowers with interstaminal nectaries (absent in P. volubilis of sect. Plukenetia ), partly connate styles, often larger fleshy fruits (although dry fruits are just as frequent in sect. Plukenetia ), and often larger seeds (usually “large” and “extra-large”). Phylogenetic relationships suggest these characters are symplesiomorphic for the palmately veined clade (P3–P5). Section Angostylidium is differentiated by its African moist to wet tropical distribution, functionally unisexual inflorescences, and funnel-shaped stylar column with conspicuously dilated and spreading free style arms ( Fig. 3L View FIG ).