摘要:

The species ofGnaphalium, Helichrysumand related genera in southern Africa have been surveyed and a number of groups of allied species detected in which the ratio of female to hermaphrodite flowers ranges from a majority of female to a majority of hermaphrodite and in some groups there are even homogamous species. Thus, the failure of the old sex‐ratio character used to separateGnaphaliumandHelichrysumis confirmed. The validity of these groupings has been tested by studying detailed characters such as the structure of the stereome (whether undivided or fenestrated) and the type of achenial hair, as well as the more usual floral characters. Most of these plants have leaves with flat or revolute margins and the occasional occurrence of involute margins is taxonomically important.GnaphaliumL. (typeG. uliginosumL.) has been redefined to includeAmphidoxaDC. andDemidiumDC. (female flowers epappose) and species with more hermaphrodite flowers then female. The stereome is undivided.Helichrysumremains a massive and highly diverse genus and includesLeontonyxCass. The stereome is normally fenestrated and the receptacle epaleate. One or two species have paleae, butRhyneawith receptacle paleate and stereome undivided is maintained. A small group of species with undivided stereomes, centred onH. marifoliumD.C., has had to be retained inHelichrysumbecause of the existence of linking species.Undivided stereome and subglobose achenial hairs enjoin the transfer ofH. vestitum(L.) Willd. and two allies, as well as the group of species centred onH. paniculatum(Thunb.) Thunb., toHelipterum, despite the lack of plumose pappus.EdmondiaCass. (H. sesamoides(L.) Willd.) with distinctive habit, involute leaves and no close relatives inHelichrysumis reinstated.PseudognaphaliumKirp., to which onlyP. oxyphyllum(DC.) Kirp. had previously been assigned, is extended to include, in its typical subgenus,HypelichrysumKirp. and a number of American species ofGnaphalium, as well as the AfricanG. undulatumL. andG. oligandrum(DC.) Hilliard&Burtt, and the AsiaticG. hypoleucumDC. andG. chrysocephalumFranch. A new subgenus,Laphangium, is created to accommodateG. luteo‐albumL. and its allies.Achyrocline(Less.) DC. has been maintained, as is done in South America, and some African species placed underHelichrysumby Moesert 1910) are returned to it.Two new genera are recognized among gnaphalioid plants with undivided stereomes:Troglophyton(based on G.capillaceumThunb.) with about seven species andPlecostachys(based on G.serpyllifoliumBerg, and includingG. polifoliumThunb.). Both genera straddle the old numerical boundary betweenGnaphaliumandHelichrysum.The monotypicHelichrysopsisKirp. is maintained. Plants of gnaphalioid aspect with fenestrated stereomes necessitate a further new genus:Vellereophyton(type G.dealbatumThunb., better known asG. candidissimumLam.) with seven species.EriosphaeraLess, andLasiopogonCass, are redefined and enlarged to include species previously placed inGnaphalium.MetalasiaandLachnospermumare redefined, with the transfer of the only large‐headed species remaining inMetalasiatoLachnospermum.Two new genera are created for plants in this affinity previously misplaced inHelichrysum. Atrichanthais based onH. gemmiferumBol. and one new species is described.Dolichothrixis established for the anomalousH. ericoides(Lam.) Pers.Iflogais briefly investigated and it is shown that the distinction between sect.Iflogaand sect.EutrichogyneBentham must be based on characters of the capitulum, not just on annual versus subshrubby habit.Lasiopogon molluginoidesDC. (=ComptonanthusNordenstam) is transferred toIflogaand the structure of the capitulum in the genus is discussed.Some earlier work on this group of plants is briefly summarized, the phytogeographical interest of the proposed arrangement is discussed and some general conclusions of

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1981.tb00958.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

All the names published under the generaGnaphalium, XeranthemumandHelichrysumin the period 1753–1800 are listed and up‐to‐date determinations are given. Appendices deal with: the specimens preserved in the Linnaean herbarium; the plants illustrated in Burman'sRariorum Africanarum Plantarum decadesand the nomenclature of a number of species that needed clarific

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1981.tb00960.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The species ofGnaphaliumnative in Africa and Madagascar are revised with the recognition of 19 species, four of which are new. Excluded and doubtful species are listed, with annotations where necessary. The misapplication of the nameG. declinatumto ten species in the geographical range from Ethiopia to the Cape of Good Hope is discussed and characters given by which they can be separated from trueG. declinatum.The distributions and relationships of all the species are given. Distribution maps of 12 species are given. Diagnostic descriptions and a key are provided.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1981.tb00961.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Iflogain southern Africa is revised and comments are offered on the northern hemisphere species,I. spicata(together withI. rueppellii) andI. obovata.Twelve species are recognized in southern Africa, two being described as new. Two natural groups, based on floral characters, are recognized and the rank of subgenus is proposed for these.Ifloga spicata, I. obovata, I. glomerata, I. anomala, I. thellungianaandI. molluginoidesconstitute subgenusIfloga; I. verticillata, I. polycnemoides, I. paronychioides, I. Candida, I. ambigua, I. repens, I. pilulifera, I. decumbens, subgenusTrichogyne.A key to the species is provided. The morphology and phytogeography of the genus are discussed.

ISSN:0024-4074    

DOI:10.1111/j.1095-8339.1981.tb00962.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY