Xylopia Section Verdcourtia D. M. Johnson & N. A. Murray, 2018

Johnson, David M. & Murray, Nancy A., 2018, A revision of Xylopia L. (Annonaceae): the species of Tropical Africa, PhytoKeys 97, pp. 1-252 : 74

IV. Xylopia Section Verdcourtia D. M. Johnson & N. A. Murray sect. nov.

Type.

Xylopia mwasumbii D. M. Johnson.

Diagnosis.

Nodes with branches from 2-3 axillary buds; outer and inner petals lanceolate, similar in length; inner petals glabrous, flat at the base and lacking differentiated fleshy basal margins; anther connectives rudimentary at apex, not overhanging the anther thecae, staminal cone rudimentary, surrounding only the bases of the ovaries, rim laciniate; carpels 2-5, the stigmas discrete, thickened and falciform; aril cupular, surrounding only the base of the seed; seed coat smooth, sarcotesta absent. Three species in Tropical Africa and at least two additional species in Madagascar.

Notes.

This species group in Xylopia was distinguished on morphological grounds ( Johnson et al. 2017) and was well supported as an early-diverging monophyletic subclade within the Stenoxylopia clade in the molecular phylogenetic analysis (Stull et al. 2017). With a more comprehensive study of Xylopia species, we find that this species group is marked by synapomorphies comparable to those used to distinguish other sections in the genus. These include glabrous inner petals, rudimentary anther connective apices, relatively short (0.7-2 mm long) and broad stigmas, and a smooth fleshy white cupular aril (Fig. 4D ). Species of this section also share outer petals spreading and inner petals erect at anthesis, stamens reduced in number (65 or fewer), and monocarps, where known, that are laterally compressed.

The section is named in memory of Bernard Verdcourt, expert on African Annonaceae and the first author to draw attention to the species of this section, through his descriptions of Xylopia "species A" and Xylopia "species B" ( Verdcourt 1971b).

Figures

Figure 4. Fruits and seeds of representative Xylopia species. A Xylopia staudtii from Democratic Republic of the Congo B Xylopia aethiopica from Republic of the Congo C Xylopia quintasii from Cameroon D Xylopia tenuipetala from Mozambique E Xylopia collina from Mozambique F Xylopia gracilipes from Mozambique G Xylopia hypolampra from Gabon H Xylopia tanganyikensis from Tanzania. A by Quentin Luke B by David Harris C, G by Thomas L. P. Couvreur D by Jonathan Timberlake E, F by Mervyn Loetter H by Noriko Itoh. C reproduced with permission of Thomas L. P. Couvreur and of the American Society of Plant Taxonomists D reproduced with the permission of Jonathan Timberlake and of the Board of Trustees, Royal Botanic Gardens Kew.