Plukenetia sect. Penninerviae Card., 2020

V. Plukenetia sect. Penninerviae Card. -McTeag. & L.J. Gillespie sect. nov. TYPE: Plukenetia penninervia Müll.Arg.

Vines or lianas, stems slender. Leaf venation pinnate, primary vein 1 (palmate, primary veins 3 in P. verrucosa ). Inflorescences bisexual racemose thyrses (racemes in P. brachybotrya ); pistillate flowers solitary at basal-most node; staminate flowers 1–3(–5)/ node in condensed cymules, sometimes appearing short racemose, or 1/node. Staminate flowers: receptacle globose or subglobose; nectaries absent or an extrastaminal annular ring (3–6-lobed, or unlobed with an uneven or undulate upper surface); stamens 6–50, anthers sessile and densely packed on the receptacle, sometimes with an outer whorl of 3–4 filamentous stamens; filaments absent or slender-cylindrical 0.2–1 mm long in outer whorl; pollen P 5 31–62 m m, E 5 39 –76 m m, tectum coarsely reticulate. Pistillate flowers: styles entirely connate into a depressed-subglobose, globose, obovoid, oblong-obovoid, stout-cylindrical, or slender-cylindrical column with a dilated apex, 0.3–4.5 mm long. Fruits 4- lobed capsules, dry, dehiscent, 0.9–1.5 cm in diam. Seeds globose, subglobose, or broadly lenticular, 4.5–7.3 3 3.7–7.1 3 3–5.2 mm, (“small” or “medium” sensu Cardinal-McTeague et al. 2019a).

The species in this section are distributed in Mexico, Central America, northwestern and Amazonian South America, and the Lesser Antilles.

Etymology —The sectional epithet is derived from penni - (Latin, feather) and - nervia (Latin, -nerved or -veined), referring to the pinnately veined leaves exhibited by most species in the section (excluding P. verrucosa ).

Discussion —Section Penninerviae refers to subclade P2 ( Fig. 1 View FIG ) and includes nine species distributed throughout the Neotropics. This section was erroneously referred to as sect. Euplukenetia by Pax and Hoffmann (1919), but that name was both invalid and incorrectly attributed to a section excluding the type species, P. volubilis . Section Penninerviae forms a major component of the pinnately veined clade (P1 1 P2), and is distinguished by having staminate flowers with sessile anthers densely packed on a globose receptacle ( Fig. 2C View FIG ), frequently with an extrastaminal annular or segmented nectary (see P. brevistyla and P. megastyla ) and/or an outer whorl of 3–4 filamentous stamens ( Fig. 2D–E View FIG ). It differs from sect. Fragariopsis by having a single pistillate flower per inflorescence and “small” seeds borne in small dry dehiscent capsules.