Mimosoideae - WikiHQ

The Mimosoideae are a traditional subfamily of trees, herbs, lianas, and shrubs in the pea family (Fabaceae) that mostly grow in tropical and subtropical climates. They are typically characterized by having radially symmetric flowers, with petals that are twice divided (valvate) in bud and with numerous showy, prominent stamens.

Recent work on phylogenetic relationships has found that the Mimosoideae form a clade nested with subfamily Caesalpinioideae and the most recent classification by The Legume Phylogeny Working Group refer to them as the Mimosoid clade within subfamily Caesalpinioideae. The group includes about 40 genera and 2,500 species.

Taxonomy

Some classification systems, for example the Cronquist system, treat the Fabaceae in a narrow sense, raising the Mimisoideae to the rank of family as Mimosaceae. The Angiosperm Phylogeny Group treats Fabaceae in the broad sense. The Mimosoideae were historically subdivided into four tribes (Acacieae, Ingeae, Mimoseae, and Mimozygantheae). However, modern molecular phylogenetics has shown that these groupings were artificial. Several informal subgroups have been proposed, but not yet described formally as tribes. Additionally, the genus Acacia was recently segregated into five genera (Acacia sensu stricto, Acaciella, Mariosousa, Senegalia, and Vachellia).

Basal Mimosoideae

Adenanthera group
Adenanthera L.
Amblygonocarpus Harms
Calpocalyx Harms
Pseudoprosopis Harms
Tetrapleura Benth.
Xylia Benth.
Entada group
Alantsilodendron Villiers
Calliandropsis H.M.Hern. & P.Guinet
Dichrostachys (DC.) Wight & Arn.
Gagnebina Neck. ex DC.
Unassigned
Aubrevillea Pellegr.
Chidlowia Hoyle
Cylicodiscus Harms
Neptunia Lour
Pentaclethra Benth.
Plathymenia Benth.

Acacia Clade (Core Mimosoideae)

right|thumb|220px|The lead tree, [[Leucaena leucocephala, is used for fiber and livestock fodder.]]

Parkia group
Anadenanthera Speg.
Parkia R.Br.
Piptadenia group
Adenopodia C.Presl
Microlobius C.Presl
Mimosa L.
Parapiptadenia Brenan
Piptadenia Benth.
Pityrocarpa Britton & Rose
Pseudopiptadenia Rauschert
Stryphnodendron Mart.
Abarema group
Abarema Pittier
Balizia Barneby & J.W.Grimes
Hydrochorea Barneby & J.W.Grimes

Ingeae grade (Paraphyletic)
Acaciella Britton & Rose
Afrocalliandra E.R. Souza & L.P. Queiroz

Albizia Durazz.
Archidendron F.Muell.
Archidendropsis I.C.Nielsen
Blanchetiodendron Barneby & J.W.Grimes
Calliandra Benth.
Cathormion (Benth.) Hassk.

Cedrelinga Ducke
Chloroleucon (Benth.) Britton & Rose

Cojoba Britton & Rose
Enterolobium Mart.
Faidherbia A.Chev.
Falcataria (I.C.Nielsen) Barneby & J.W.Grimes

Hesperalbizia Barneby & J.W.Grimes
Inga Mill.
Leucochloron Barneby & J.W.Grimes
Lysiloma Benth.
Macrosamanea Britton & Rose

Pararchidendron I.C.Nielsen
Pseudosamanea Harms
Samanea (Benth.) Merr.
Sanjappa E.R. Souza & Krishnaraj
Serianthes Benth.
Thailentadopsis Kosterm.
Viguieranthus Villiers
Wallaceodendron Koord.
Zapoteca H.M.Hern.
Zygia P.Browne
Pithecellobium group

†Acacioxylon Schenk 1883
†Adenantheroxylon Prakash & Tripathi 1968
†Albizinium Prakash 1975
†Albizzioxylon Nikitin 1935
†Anadenantheroxylon Brea et al. 2001
†Cathormion Gros 1990
†Dichrostachyoxylon Müller-Stoll & Mädel 1967
†Eucacioxylon Müller-Stoll & Mädel 1967
†Ingoxylon Müller-Stoll & Mädel 1967
†Menendoxylon Lutz 1979
†Metacacioxylon Gros 1981
†Microlobiusxylon Franco & Brea 2010
†Mimosoxylon Müller-Stoll & Mädel 1967
†Mimosaceoxylon Lakhanpal & Prakash1970
†Paraalbizioxylon Gros 1992
†Paracacioxylon Müller-Stoll & Mädel 1967
†Piptadenioxylon Suguio & Mussa 1978
†Prosopisinoxylon Martínez
†Tetrapleuroxylon Müller-Stoll & Mädel 1967

Systematics

Modern molecular phylogenetics suggests the following relationships:) is a wide-ranging, polyphyletic tribe of legumes in the Mimosoideae that is native to the tropics, subtropics, and warm-temperate regions. It includes five or six genera and some 1,450 species.

Subdivision – 5 or 6 genera
Acacia Mill. – type genus His Acacieae tribe of 1842 included many genera that were subsequently assigned to tribe Ingeae Benth. In 1875, however, Bentham narrowed his definition of Acacieae so as to include only Acacia Mill.

The only morphological character of Acacieae used to distinguish it from the Ingeae is the presence of free stamens (as in tribe Mimoseae).

The tribal position of monotypic genus Faidherbia A. Chevalier is equivocal. In the latter case, tribe Acacieae may conform to genus Acacia s.l., pending the latter's relationship to other mimosoid genera. Faidherbia is troublesome as its stamens are shortly united at their base and its pollen is similar to some taxa in the Ingeae. Where they have spines, these are modified stipules. In some, prickles arise from the stem's cortex and epidermis. The leaves are bipinnate or are modified to vertically oriented phyllodes. A few have cladodes rather than leaves. Extrafloral nectaries may be present on the petiole and rachis, and the pinnule tips may carry protein-lipid Beltian bodies. and the sap of various species hardens into gum.