Monday, April 30, 2018

[Botany • 2018] A Revision of Xylopia L. (Annonaceae): The Species of Tropical Africa

 Xylopia aethiopica from Gabon Xylopia longipetala from Mali, representing a record for the country not otherwise documented Xylopia piratae from Ivory Coast Xylopia odoratissima from Zambia Xylopia arenaria from Tanzania

in Johnson & Murray, 2018.

A revision of the 45 species of the pantropical genus Xylopia in Tropical Africa includes descriptions of six new species and a new section of the genus. The fruits and seeds of Xylopia show specializations that promote vertebrate dispersal, primarily by hornbills and monkeys. Over half of the African species have an Area of Occupancy (AOO) less than 80 km2, suggesting that they are in need of protection. African species are classified into five sections. Section Neoxylopia , with four species, is centered in the Guineo-Congolian Region and includes Xylopia globosa sp. nov. Section Ancistropetala, with three species, occurs in the same region. Both of these sections are endemic to Africa. Section Xylopia, which extends to Madagascar and the American tropics, has only a single species in Africa, X. aethiopica. The three species of section Verdcourtia sect. nov. are restricted to the East African coast and Madagascar. The largest number of African species, (34) belong to section Stenoxylopia, in which the seeds lack the arils found in the other sections and instead have a fleshy sarcotesta. Section Stenoxylopia is divided into two informal groups, one centered in eastern and southern Africa (X. odoratissima group) and the other centered in the wetter forests of western and central Africa (X. acutiflora group). Five new species are described in section StenoxylopiaXylopia nilotica sp. nov. from Sudan, South Sudan, and Uganda, Xylopia calva sp. nov. from Nigeria and Cameroon, which is allied to X. phloiodora, and Xylopia monticola sp. nov. from Nigeria and Cameroon, X. piratae sp. nov. from Ivory Coast and Ghana, and X. unguiculata sp. nov. from Gabon. The latter three species are segregates of the former Xylopia acutiflora s. l. One new combination is made at the species level, X. shirensis comb. nov. Keys, descriptions, illustrations, distribution maps, and an index to numbered collections document diversity and assist with species identification. The name Unona oliveriana Baill. was found to pre-date the name Unona lepidota Oliv., requiring the combination Meiocarpidium oliverianum comb. nov.

Keywords: Xylopia, pantropical Annonaceae, Tropical Africa, long distance dispersal, bird/monkey syndrome, X. aethiopica, conservation, new species

Figure 3. Flowers of representative Xylopia species.
A Flower from type collection of Xylopia globosa from Gabon B Xylopia tenuipetala from Mozambique C Xylopia quintasii from Gabon D Xylopia aethiopica from Gabon E Xylopia longipetala from Mali, representing a record for the country not otherwise documented F Xylopia piratae from Ivory Coast G Xylopia odoratissima from Zambia H Xylopia arenaria from Tanzania I Xylopia collina from Tanzania.
A, D by Thomas L. P. Couvreur B by Frances Chase C by Ehoarn Bidault E by Philip Birnbaum F by Céline Pirat G by Warren McClelland H and I by D. M. Johnson.

Xylopia globosa D. M. Johnson & N. A. Murray, sp. nov.

Xylopia nilotica D. M. Johnson & N. A. Murray, sp. nov.

 Xylopia calva D. M. Johnson & N. A. Murray, sp. nov.

 Xylopia monticola D. M. Johnson & N. A. Murray, sp. nov.

Xylopia piratae D. M. Johnson & N. A. Murray, sp. nov.

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 Lötter 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.

 David M. Johnson and Nancy A. Murray. 2018. A Revision of Xylopia L. (Annonaceae): The Species of Tropical Africa.  PhytoKeys. 97: 1-252.  DOI:  10.3897/phytokeys.97.20975

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