David J. Goyder

Asclepiadeae classification: evaluating the phylogenetic relationships of New World Asclepiadoideae (Apocynaceae)

To provide an overview of New World Asclepiadoideae, we here evaluate Asclepiadeae classification by comparing the taxonomic arrangement of subtribes with a topology obtained through analyses of two plastid DNA regions (trnL intron and trnL-F intergenic spacer) for 111 species of Asclepiadoideae representing the major lineages of the subfamily. Without Jobinia, Nephradenia and Barjonia, Asclepiadeae are not monophyletic. The monotypic African genus Eustegia, with pendent pollinia, may represent the sister clade of MarsdenieaeCeropegieae, the group composed of plants with erect pollinia. Metastelmatinae including African plants are also non-monophyletic, and the circumscription of the recently re-instated Cynanchinae should be studied further. Overall, Asclepiadeae are composed of three main clades. The Old World Astephaninae are the sister group of the other Asclepiadeae, which are divided into the ACTG (Asclepiadinae, Cynanchinae, Tylophorinae and Glossonematinae) and MOG (Metastelmatinae, Oxypetalinae and Gonolobinae) clades. According to this study, the New World Asclepiadoideae fall into just four clades: (1) Marsdenia(Marsdenieae), (2) Asclepias (Asclepiadinae, Asclepiadeae), (3) Cynanchum subgenus Mellichampia(Cynanchinae, Asclepiadeae), and (4) MOG, the clade comprising the majority of New World Asclepiadoideae.

Phylogenetics of the New World Subtribes of Asclepiadeae (Apocynaceae—Asclepiadoideae): Metastelmatinae, Oxypetalinae, and Gonolobinae

Abstract Analysis of the trnT-trnL spacer, the trnL intron, the trnL-trnF spacer, and the rps16 intron of 106 species in 34 of the 45 genera of New World Asclepiadeae in the former subtribes Metastelmatinae, Oxypetalinae, and Gonolobinae shows that these genera form a well-supported clade (“MOG”). The small Andean genus Pentacyphus is sister to the remaining MOG clade. The former Gonolobinae form a well-supported subclade closely related to members of Tassadia, Funastrum, and former Oxypetalinae. The only genera that are monophyletic as presently circumscribed are Tassadia and Funastrum. The separation of Tweedia from Oxypetalum is justified by our results. Philibertia is monophyletic only if Amblystigma, Fontellaea, Melinia, Mitostigma, and Podandra are also included. Most species of Blepharodon and Hemipogon are not monophyletic with the respective type species. Some former Astephanus and Cynanchum species as well as the monotypic Grisebachiella are imbedded in Diplolepis (D. descolei, D. geminiflora, D. hieronymi, D. boerhaviifolia, and D. nummulariifolia). The neglected tribe Orthosieae is recognized at subtribal level, Orthosiinae. Chromosome numbers (as far as known) indicate a tendency for reduction in several clades. This study provides a framework for future study of the American MOG genera and highlights areas that need further attention.

Phylogenetic relationships in subtribe asclepiadinae (Apocynaceae: Asclepiadoideae)

Abstract A first approximation of evolutionary relationships within the Asclepiadinae (Apocynaceae: Asclepiadoideae) is inferred from two DNA data sets, from the nuclear ITS region, and from plastid trnT-L and trnL-F spacers and trnL intron. Both the subtribe as a whole and the phylogenetic radiation of largely herbaceous genera around Asclepias are monophyletic and well supported. While resolution within the Asclepias complex is limited, the lineages identified demonstrate that current generic delimitation is unsatisfactory. Asclepias should be either restricted to New World members of the subtribe or expanded to encompass the entire radiation. In the African species, it is shown that, although the corona is taxonomically important for recognizing species, it can be misleading as an indicator of phylogenetic relationship. Vegetative similarities often prove a more reliable guide, but more detailed studies are needed to refine these lineages and to detect morphological characters to aid in their practical recognition.

The new genus Minaria (Asclepiadoideae, Apocynaceae)

Combined analyses of plastid regions indicate that the genus Ditassa (Asclepiadoideae, Apocynaceae) is polyphyletic and reveal a highly supported clade composed of shrubby species with minute leaves. These molecular data provide clear support for the recognition of a segregate genus from Ditassa, which we propose here as Minaria. Keys to distinguish Minaria from closely related genera and to identify the species of Minaria are provided. Eighteen nomenclatural combinations are proposed and the new species M. campanuliflora is described. The new genus is centred on eastern Brazil with two more widely distributed species extending as far as eastern Bolivia and NE Argentina. All the species occur in the state of Minas Gerais, Brazil, and it is from Minas that the name is derived; fourteen are endemic to the Espinhaco Range, and most are narrow endemics.

A synopsis of Asclepias (Apocynaceae: Asclepiadoideae) in tropical Africa

SummaryIn preparation for two major regional Flora accounts, Asclepias has been reassessed in tropical Africa. 38 species not assigned to the allied genera Aspidoglossum, Glossostelma, Gomphocarpus, Margaretta, Pachycarpus, Stathmostelma, Stenostelma or Xysmalobium are recognised in the region. Nine species and one subspecies are described for the first time. The inclusion of Trachycalymma again within Asclepias requires four new combinations. A further three new names or combinations are required for the transfer of Odontostelma welwitschii, Schizoglossum alpestre and Stathmostelma verdickii to Asclepias. Five names are lectotypified, and a neotype proposed for Gomphocarpus meliodorus. The conservation status of all species is assessed.

Xysmalobium samoritourei (Apocynaceae: Asclepiadoideae), a new species from the Guinea Highlands of West Africa

SummaryXysmalobium samoritourei Goyder (Apocynaceae: Asclepiadoideae) is described from the highlands of Sierra Leone and Guinea (Conakry) and illustrated. Its conservation status is assessed.

Cibirhiza spiculata (Apocynaceae), a remarkable new species from eastern Ethiopia

SummaryThe new species Cibirhiza spiculata Thulin & Goyder, from Acacia-Commiphora bushland on sand in the Somali National Regional State (Ogaden) of Ethiopia, is described and illustrated. Its conservation status has been assessed. A molecular phylogenetic analysis confirms its placement in the tribe Fockeeae and indicates a position of the new species as sister to C. albersiana. The almost obsolete anther appendages, the outer corona with spreading lobes, as well as the pollinia with apparently single pollen grains, also support its placement in Cibirhiza. However, C. spiculata differs markedly from both previously known species of this genus (C. dhofarensis in Oman and Yemen and C. albersiana in Tanzania and Zambia) by its narrowly linear, subsessile leaves and by the inner corona lobes that are curved inwards over the gynostegium and each ending in a spinulose head.

Nomenclatural changes resulting from the transfer of tropical African Sarcostemma to Cynanchum (Apocynaceae: Asclepiadoideae)

SummaryFour species of tropical African Sarcostemma are transferred to Cynanchum together with two subspecies of S. viminale. In addition, Sarcostemma mulanjense is reduced to subspecific rank under C. viminale.

A brief botanical survey into Kumbira forest, an isolated patch of Guineo-Congolian biome

Abstract Kumbira forest is a discrete patch of moist forest of Guineo-Congolian biome in Western Angola central scarp and runs through Cuanza Norte and Cuanza Sul province. The project aimed to document the floristic diversity of the Angolan escarpment, a combination of general walk-over survey, plant specimen collection and sight observation was used to aid the characterization of the vegetation. Over 100 plant specimens in flower or fruit were collected within four identified vegetation types. The list of species includes two new records of Guineo-Congolian species in Angola, one new record for the country and one potential new species.

Philibertia (Apocynaceae:Asclepiadoideae) — additional notes and three new species for Bolivia

SummaryThree new species of Philibertia (Apocynaceae:Asclepiadoideae), P. alba Goyder, P. urceolata Goyder and P. zongoensis Goyder are described from Bolivia and illustrated. Preliminary conservation assessments are made for these species. New records are reported for two further species.