Monadelpha L.J.Gillespie & Card.-McTeag., 2020

Gillespie, Lynn J., Cardinal-McTeague, Warren M. & Wurdack, Kenneth J., 2020, Monadelpha (Euphorbiaceae, Plukenetieae), a new genus of Tragiinae from the Amazon rainforest of Venezuela and Brazil, PhytoKeys 169, pp. 119-135 : 119

Monadelpha L.J.Gillespie & Card.-McTeag. gen. nov.

Tragia section Monadelphae L.J.Gillespie, Novon 4: 331. 1994.

Diagnosis.

Similar to Tragia and other Tragiinae genera but differing in having 5-colpate pollen and monadelphous stamens with filaments entirely connate into an elongate, cylindrical staminal column with anthers tightly clustered together at apex.

Type and only known species.

Monadelpha guayanensis (L.J.Gillespie) L.J.Gillespie & Card.-McTeag.

Description.

Habit climbing vines, apparently monoecious; latex absent; stems twining; stems, leaves and inflorescences with stinging and simple hairs. Stipules narrowly triangular or lanceolate, small, caducous. Leaves simple, alternate, evergreen, petiolate, eglandular; blades elliptic, ovate-elliptic, broadly elliptic, broadly ovate-elliptic, or suborbicular, chartaceous, apex acuminate, base narrowly cordate, margins irregularly serrulate or denticulate with minute glandular setae, venation pinnate; petiolar and laminar glands absent. Inflorescences slender racemes, unisexual, flowers single per node in bract axil; bracts small, lanceolate or narrowly lanceolate, eglandular; staminate inflorescence axillary; pistillate inflorescence (known only in fruiting stage) terminal but appearing leaf-opposed. Staminate flowers pedicellate; sepals 5, narrowly oblong, valvate; corolla and disc absent; stamens apparently 5, monadelphous; filaments connate into an elongate, ± cylindrical staminal column, bearing a dense cluster of ± 5 anthers; pollen 5-colpate, oblate-spheroidal to suboblate, amb pentagonal, exine tectate-perforate, tectum foveolate and microverrucate, colpi with uneven margins. Pistillate flowers (description based on old flowers on infructescence axis) pedicellate; sepals 6, ovate, distinctly imbricate, margins entire; corolla and disc absent; ovary 3-locular with 1 ovule per locule, 3-lobed, densely covered with stinging hairs; styles 3, long-cylindrical, mostly distinct, connate basally for 10-25% length, papillose at apex. Fruits 3-lobed capsules, dehiscing into 3 bivalved mericarps; pericarp woody, sparsely covered with stinging hairs; columella persistent, with 3 perpendicular apical arms; seeds 3, subglobose, abaxial surface somewhat obtusely angular, ecarunculate; sepals persistent.

Etymology.

The genus name is combined from monos (Greek, one) and adelphos (Greek, brother), and refers to monadelphous with filaments united and to Tragia section Monadelphae .