D.M. Johnson

Bio: D.M. Johnson is an academic researcher from Ohio Wesleyan University. The author has contributed to research in topics: Xylopia & Xylopia ferruginea. The author has an hindex of 1, co-authored 1 publications receiving 8 citations.

A contribution to the systematics of Xylopia (Annonaceae) in Southeast Asia

Abstract: Herbarium and field study of Xylopia L. (Annonaceae) for the Flora of Peninsular Malaysia and the Flora of Thailand projects has clarified regional diversity patterns within this ecologically significant lowland rainforest genus. Two species groups represented within Southeast Asian floras are delineated, one centred on Xylopia ferruginea (Hook.f. & Thomson) Baill. and the other on Xylopia malayana Hook.f. & Thomson. In the Xylopia ferruginea group, a new species, Xylopia erythrodactyla D.M.Johnson & N.A.Murray, is distinguished from X. ferruginea, and a new combination, Xylopia sumatrana (Miq.) D.M.Johnson & N.A.Murray, is proposed, based on an earlier name for the species currently known as Xylopia stenopetala Oliv. In the Xylopia malayana group, review of the species Xylopia elliptica Maingay ex Hook.f. & Thomson resulted in the recognition of three additional species: Xylopia platycarpa D.M.Johnson & N.A.Murray, from southern Thailand and northwestern Peninsular Malaysia, Xylopia ngii D.M.Johnson & N.A.Murray, from Peninsular Malaysia, Sumatra and Borneo, and Xylopia heterotricha D.M.Johnson & N.A.Murray, from Sumatra and Borneo. The taxon Xylopia malayana Hook.f. & Thomson var. obscura Kochummen is placed in synonymy under Xylopia elliptica sensu stricto. Xylopia fusca Maingay ex Hook.f. & Thomson var. sessiliflora Kochummen & Whitmore is distinguished from Xylopia fusca, and raised to species status as Xylopia sessiliflora (Kochummen & Whitmore) D.M.Johnson & N.A.Murray. We recognise 23 Xylopia species in the Sundaic region of Southeast Asia, and provide evidence that additional collecting and taxonomic analysis in the region is needed.

Plastid and Seed Morphology Data Support a Revised Infrageneric Classification and an African Origin of the Pantropical Genus Xylopia (Annonaceae)

Abstract: The floristic treatment of Engler and Diels, published in 1901, provides the only infrageneric classification of the pantropical genus Xylopia (Annonaceae) Here we test and extend that classification using molecular and seed morphology characters Phylogenetic relationships were reconstructed using data from four plastid regions obtained from 44 of the approximately 165 species in the genus, recovering four well-supported major clades Seed characters were examined for these taxa, and six aril morphologies, three previously undocumented, were distinguished; we also document the presence of a sarcotesta on the seeds of many species Molecular and seed data support recognition of five sections within the genus; one, Xylopia sect Rugosperma, is proposed here as new Our phylogenetic results suggest an African origin for the genus and reveal complex biogeographic patterns, likely facilitated by long-distance dispersal

Revisions of Ruizodendron and Pseudephedranthus (Annonaceae) including a new species and an overview of most up-to-date revisions of Neotropical Annonaceae genera.

Abstract: We present revisions of the Neotropical genera Ruizodendron and Pseudephedranthus (Annonaceae). Ruizodendron includes a single species R. ovale. Pseudephedranthus now comprises two species, with the description of the new species P. enigmaticus sp. nov. extending the range of the genus beyond the Upper Rio Negro region of Brazil (Amazonas) and adjacent Venezuela (P. fragrans), to include Guyana, Suriname, and the Brazilian state of Para. An overview is provided of current revisions of Neotropical Annonaceae genera that will aid in accessing proper species information for this frequently encountered tropical rain forest family.

A revision of Xylopia L. (Annonaceae): the species of Madagascar and the Mascarene islands

Abstract: We recognize 30 species of the pantropical genus Xylopia L. from Madagascar and an additional three species from the Mascarene Islands. Of the six sections of the genus, three are represented in the region: sect. Xylopia, sect. Verdcourtia, and sect. Stenoxylopia. All species are endemic, and many are microendemics of conservation concern. The greatest species richness occurs in humid forests below 1000 m. Taxonomic review supports the hypothesis that the genus dispersed to Madagascar from continental Africa five times. Ten new species are described: Xylopia anomala D.M.Johnson & N.A.Murray, sp. nov., X. australis D.M.Johnson & N.A.Murray, sp. nov., X. carinata D.M.Johnson & N.A.Murray, sp. nov., X. galokothamna D.M.Johnson & N.A.Murray, sp. nov., X. lokobensis D.M.Johnson & N.A.Murray, sp. nov., X. longirostra D.M.Johnson & N.A.Murray, sp. nov., X. marojejyana D.M.Johnson & N.A.Murray, sp. nov., X. ravelonarivoi D.M.Johnson & N.A.Murray, sp. nov., X. retusa D.M.Johnson & N.A.Murray, sp. nov., and X. sclerophylla D.M.Johnson & N.A.Murray, sp. nov. An identification key, technical descriptions, illustrations, and distribution maps are provided.