du changement dans les etiquettes

importants ya alainc qui viens de me prevenir d'un changement dans la nomenclature chez les plantes ! les Monadenium deviennent des Euphorbia ...et me d'mander pas pourquoi


Dear Euphorbophiles,
recently some interesting taxonomical changes took place in and around genus Euphorbia (Euphorbiaceae). Here is a short review:

Euphorbia is one of the largest genera in plant kingdom. Hitherto it represented the largest part of subtribe Euphorbiianae Griseb. and there was accompanied by the small so called satellite genera Cubanthus, Elaeophorbia, Endadenium, Monadenium, Synadenium and Pedilanthus.

For a long time many botanist tried to split the huge and as paraphyletic recognised genus Euphorbia into smaller and monophyletic genera. An instance is the separation of Chamaesyce by Gray (1826). As however the difference between Chamaesyse and Euphorbia was restricted to the plant shape and as there are intermediate species to Euphorbia's subgenus Agaloma, Chamaesyce was never generally accepted. In the past similar troubles to find reliable borderlines between Euphorbia and separated genera resulted in lots of synonyms like Agaloma, Anthacantha, Arthrothamnos, Dactylanthus, Esula, Lacanthis, Lyciopsis, Medusae, Poinsettia, Sterigmanthe, Tithymalus, Treisia etc. which sometimes became accepted as subgenera or sections of Euphorbia.

A genus in modern sense must be monophyletic. What means that it must have a common ancestor and must contain all groups that stem from this ancestor, the ancestor itself (if not extinct), but no other group. However, until recently Euphorbia wasn't monophyletic but paraphyletic as for instance it contained all species with true cyathia - besides those with derived characteristics like strongly reduced primary shoots (Chamaesyce), fused together nectar glands (Monadenium, Endadenium, Synadenium), fused together bracts and bilateral symmetric cyathia (Pedilanthus) and fruits that remain fleshy (Elaeophorbia). Moreover several intermediate species cast the borderline between Euphorbia and the satellites into doubt. There are "good" Euphorbia species that for instance have partly fused together bracts, bilateral symmetric cyathia, nectar glands that tend to fuse together and fruits that remain fleshy for a very long time. And there are Monadeniums in which the glands are only imperfectly fused together.

Only recently comparative DNA studies established order in the muddle. Steinmann & Porter (2002), Steinmann (2003) und Bruyns & al. (2006) demonstrated that Euphorbia consist of about 40 groups, and that the satellite genera, among Euphorbia species, nest deep within genus Euphorbia. If the satellite genera should be conserved, each the about 40 groups then must be given the rank of a genus for its own. What would result in difficult to characterise genera that can't be told apart by appearance and sometimes hardly by their DNA, up to 1500 new names and all in all a much larger muddle than before. In order to avoid this senseless splitting, the above mentioned botanists stroke the only reasonable path, enlarged the concept of Euphorbia a little and integrated the satellites. Besides the not yet processed genus Cubanthus (related to Pedilanthus and containing three non-succulent species) all species of subtribe Euphorbiinae now belong to Euphorbia.

Another result of the DNA studies is that Euphorbia consists of only 4 subgenera (Chamaesyce, Esula, Euphorbia, Rhizanthium) which hardly align with the subgenera known from traditional botany.
- Monadenium, Synadenium and Endadenium are not separable and together with the former subgenus Lacanthis (CoT relationship) belong to subgenus Euphorbia which so far only contained species with spines on shields.
- Rhizanthium contains most members of the former sections Anthacantha, Dactylanthes, Meleuphorbia, Treisia and Trichadenia.
- Chamaesyce contains the former subgenera Agaloma, Chamaesyce and Poinsettia as well as the former section Arthrothamnus whose members don't show any corporal similarities to typical Chamaesyce.

There is a list of ALL currently accepted taxa of Euphorbia on this Wikipedia page:
http://en.wikipedia.org/wiki/List_of_Euphorbia_species
In this list all (more or less) succulent species are marked and all former names of Elaeophorbia, Endadenium, Monadenium, Synadenium und Pedilanthus are mentioned as synonyms to the new names.

Literature:
- Steinmann, V. W. & Porter, J. M.: Phylogenetic relationships in Euphorbieae (Euphorbiaceae) based on ITS and ndhF sequence data. Ann. Missouri Bot. Gard. 89 (2002): 453–490.
- Steinmann, V. W.: The submerion of Pedilanthus into Euphorbia (Euphorbiaceae). Acta Botanica Mexicana (2003), 65: 45-50
- Bruyns, Peter V. & al.: The A new subgeneric classification for Euphorbia (Euphorbiaceae) in southern Africa based on ITS and psbA-trnH sequence data. Taxon 55 (2) May 2006: 397–420

Remark:
There are two current conflicts caused by the new names by Bruyns.
- To Euphorbia kaessneri (N.E.Br.) Bruyns 2006 (syn. Monadenium kaessneri) there is already a Euphorbia kaessneri Pax 1909.
To Euphorbia pseudograntii Bruyns 2006 (syn. Synadenium grantii) there is already a Euphorbia pseudograntii Pax 1901.
In a personal correspondence Dr. Peter Bruyns informed me that he is aware of the conflicts and will give a correction in an addendum to his paper.

ce qui donne:
Elaeophorbia drupifera -> Euphorbia drupifera
Elaeophorbia grandifolia -> Euphorbia grandifolia
Elaeophorbia hiernii -> Euphorbia hiernii
Endadenium gossweileri (Basonym: Monadenium gossweileri) -> Euphorbia neogossweileri
Monadenium angolense -> Euphorbia neoangolensis
Monadenium arborescens -> Euphorbia neoarborescens
Monadenium bianoense -> Euphorbia bianoensis
Monadenium bodenghieniae -> Euphorbia bodenghieniae
Monadenium cannellii -> Euphorbia iancannellii
Monadenium capitatum -> Euphorbia neocapitata
Monadenium catenatum -> Euphorbia catenata
Monadenium chevalieri -> Euphorbia chevalieri
Monadenium clarae -> Euphorbia clarae
Monadenium coccineum -> Euphorbia neococcinea
Monadenium crenatum -> Euphorbia crenata
Monadenium crispum -> Euphorbia neocrispa
Monadenium cupricola -> Euphorbia cupricola
Monadenium cupulare -> Euphorbia cupularis
Monadenium descampsii -> Euphorbia descampsii
Monadenium dilunguense -> Euphorbia dilunguensis
Monadenium discoideum -> Euphorbia discoidea
Monadenium echinulatum -> Euphorbia echinulata
Monadenium elegans -> Euphorbia biselegans
Monadenium ellenbecki -> Euphorbia bisellenbeckii
Monadenium erubescens (Basonym: Lortia erubescens) -> Euphorbia neoerubescens
Monadenium filiforme (Basonym: M. chevalieri var. filiforme) -> Euphorbia filiformis
Monadenium friesii -> Euphorbia friesii
Monadenium fwambense -> Euphorbia fwambensis
Monadenium gillettii -> Euphorbia neogillettii
Monadenium gladiatum (Basonym: M. yattanum var. gladiatum) -> Euphorbia gladiata
Monadenium globosum -> Euphorbia bisglobosa
Monadenium goetzei -> Euphorbia neogoetzei
Monadenium gracile -> Euphorbia neogracilis
Monadenium guentheri -> Euphorbia guentheri
Monadenium hedigerianum -> Euphorbia hedigeriana
Monadenium herbaceum -> Euphorbia herbacea
Monadenium heteropodum -> Euphorbia heteropoda
.Monadenium heteropodum var. formosum (Basonym: Monadenium schubei var. formosum) -> Euphorbia heteropoda var. formosa
.Monadenium heteropodum var. heteropodum -> Euphorbia heteropoda var. heteropoda
Monadenium hirsutum -> Euphorbia pseudohirsuta
Monadenium invenustum -> Euphorbia invenusta
.Monadenium invenustum var. angustum -> Euphorbia invenusta var. angusta
.Monadenium invenustum var. invenustum -> Euphorbia invenusta var. invenusta
Monadenium kaessneri -> Euphorbia kaessneri (Name conflict, to be corrected!)
Monadenium kimberleyanum -> Euphorbia kimberleyana
Monadenium kundelunguense -> Euphorbia kundelunguensis
Monadenium laeve -> Euphorbia pseudolaevis
Monadenium letestuanum -> Euphorbia letestuana
Monadenium lindenii -> Euphorbia lindenii
Monadenium lugardiae -> Euphorbia lugardiae
Monadenium mafingense -> Euphorbia mafingensis
Monadenium magnificum -> Euphorbia magnifica
Monadenium mamfwense -> Euphorbia mamfwensis
Monadenium montanum -> Euphorbia neomontana
Monadenium nervosum -> Euphorbia pseudonervosa
Monadenium nudicaule -> Euphorbia pseudonudicaulis
Monadenium orobanchoides -> Euphorbia orobanchoides
.Monadenium orobanchoides var. calycinum -> Euphorbia orobanchoides var. calycina
.Monadenium orobanchoides var. orobanchoides -> Euphorbia orobanchoides var. orobanchoides
Monadenium parviflorum -> Euphorbia neoparviflora
Monadenium pedunculatum -> Euphorbia neopedunculata
Monadenium petiolatum -> Euphorbia pseudopetiolata
Monadenium pseudoracemosum -> Euphorbia pseudoracemosa
.Monadenium pseudoracemosum var. lorifolium -> Euphorbia pseudoracemosa var. lorifolia
. Monadenium pseudoracemosum var. pseudoracemosum -> Euphorbia pseudoracemosa var. pseudoracemosa
Monadenium pudibundum -> Euphorbia pudibunda
.Monadenium pudibundum var. lanatum -> Euphorbia pudibunda var. lanata
.Monadenium pudibundum var. pudibundum -> Euphorbia pudibunda var. pudibunda
.Monadenium pudibundum var. rotundifolium -> Euphorbia pudibunda var. rotundifolia
Monadenium reflexum -> Euphorbia neoreflexa
Monadenium renneyi -> Euphorbia renneyi
Monadenium rhizophorum -> Euphorbia rhizophora
Monadenium ritchiei -> Euphorbia ritchiei
.Monadenium ritchiei ssp. marsabitense -> Euphorbia ritchiei ssp. marsabitensis
.Monadenium ritchiei ssp. nyambense -> Euphorbia ritchiei ssp. nyambensis
.Monadenium ritchiei ssp. ritchiei -> Euphorbia ritchiei ssp. ritchiei
Monadenium rubellum (Basonym: M. montanum var. rubellum) -> Euphorbia neorubella
Monadenium rugosum -> Euphorbia neorugosa
Monadenium schaijesii -> Euphorbia schaijesii
Monadenium shebeliense -> Euphorbia shebeliensis
Monadenium simplex -> Euphorbia pseudosimplex
Monadenium spectabile -> Euphorbia spectabilis
Monadenium spinescens (Basonym: Stenadenium spinescens) -> Euphorbia neospinescens
Monadenium spinulosum -> Euphorbia spinulosa
Monadenium stapelioides -> Euphorbia neostapeliodes
.Monadenium stapelioides var. congestum -> Euphorbia neostapeliodes var. congesta
.Monadenium stapelioides var. stapelioides -> Euphorbia neostapeliodes var. neostapeliodes
Monadenium stellatum -> Euphorbia pseudostellata
Monadenium stoloniferum (Basonym: M. rhizophorum var. stoloniferum) -> Euphorbia neostolonifera
Monadenium torrei -> Euphorbia torrei
Monadenium trinerve -> Euphorbia pseudotrinervis
Monadenium virgatum -> Euphorbia neovirgata
Monadenium yattanum -> Euphorbia yattana
Pedilanthus bracteatus -> Euphorbia bracteata
Pedilanthus calcaratus -> Euphorbia calcarata
Pedilanthus coalcomanensis -> Euphorbia coalcomanensis
Pedilanthus connatus -> Euphorbia colligata
Pedilanthus cymbiferus -> Euphorbia cymbifera
Pedilanthus diazlunanus -> Euphorbia diazlunana
Pedilanthus finkii -> Euphorbia finkii
Pedilanthus gracilis -> Euphorbia dressleri
Pedilanthus macrocarpus -> Euphorbia lomelii
Pedilanthus peritropoides -> Euphorbia peritropoides
Pedilanthus personatus -> Euphorbia personata
Pedilanthus pulchellus -> Euphorbia conzattii
Pedilanthus tehuacanus -> Euphorbia tehuacana
Pedilanthus tithymaloides -> Euphorbia tithymaloides
.Pedilanthus tithymaloides ssp. angustifolius -> Euphorbia tithymaloides ssp. angustifolia
.Pedilanthus tithymaloides ssp. bahamensis -> Euphorbia tithymaloides ssp. angustifolia
.Pedilanthus tithymaloides ssp. jamaicensis -> Euphorbia tithymaloides ssp. jamaicensis
.Pedilanthus tithymaloides ssp. padifolius -> Euphorbia tithymaloides ssp. jamaicensis
.Pedilanthus tithymaloides ssp. parasiticus -> Euphorbia tithymaloides ssp. parasitica
.Pedilanthus tithymaloides ssp. retusus -> Euphorbia tithymaloides ssp. retusa
.Pedilanthus tithymaloides ssp. smallii -> Euphorbia tithymaloides ssp. smallii
.Pedilanthus tithymaloides ssp. tithymaloides -> Euphorbia tithymaloides ssp. tithymaloides
Pedilanthus tomentellus -> Euphorbia cyri
Synadenium angolense -> Euphorbia triangolensis
Synadenium calycinum -> Euphorbia syncalycina
Synadenium cameronii -> Euphorbia syncameronii
Synadenium compactum -> Euphorbia bicompacta
.Synadenium compactum var. compactum -> Euphorbia bicompacta var. bicompacta
.Synadenium compactum var. rubrum -> Euphorbia bicompacta var. rubra
Synadenium cymosum -> Euphorbia neocymosa
Synadenium glabratum -> Euphorbia neoglabrata
Synadenium glaucescens -> Euphorbia neoglaucescens
Synadenium grantii -> Euphorbia pseudograntii (Name conflict, to be corrected!)
Synadenium halipedicola -> Euphorbia neohalipedicola
Synadenium kirkii -> Euphorbia kirkii
Synadenium molle -> Euphorbia pseudomollis
Synadenium pereskiifolium -> Euphorbia pereskiifolia
Synadenium volkensii -> Euphorbia pseudovolkensii

:_hallucine: pourquoi? :_rire3:

Bah ils le disent, un genre dorénavant comprend des espèces dont on pense qu’elles ont un ancêtre commun.
Le genre Euphorbia était si vaste que les botanistes cherchaient depuis longtemps comment le réduire. Déjà, ce genre ne comprenait pas que des espèces ayant un ancêtre commun loin de là.
Le cyathia en est un exemple : aucun ancêtre commun avec les Euphorbias.
Confusion dans ce genre dont il y avait beaucoup d’espèces comportant un nom d’Euphorbia + un synonyme d’un autre genre botanique.
Il y a donc eu un gros nettoyage principalement après étude de l’ADN des végétaux.
La liste de Pedro est donc une liste de plantes acceptées dans le genre – Une autre liste existe assurément et beaucoup plus longue, d’euphorbias reclassées dans un autre genre.

Pour les Monadenium, une recherche ADN a prouvé récemment qu'ils avaient des ancêtres communs avec les Euphorbias, d'où leur reclassement.

Et bien si l'autre liste est plus longue alors comme livre de chevet ce serait un sacré somnifère.
Pourquoi c'est si compliqué leurs noms ? :_snif: