Picrodendraceae

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Picrodendraceae
Tetracoccus dioicus, male flowers and fruit

Tetracoccus dioicus , male flowers and fruit

Systematics
Eudicotyledons
Nuclear eudicotyledons
Rosids
Eurosiden I
Order : Malpighiales (Malpighiales)
Family : Picrodendraceae
Scientific name
Picrodendraceae
Small

The picrodendraceae is a family from the order of Malpighienartigen (Malpighiales). It is close to the milkweed family (Euphorbiaceae) to which it was previously counted and has so far been little researched.

description

The species usually grow as evergreen to deciduous trees, less often than shrubs. The mostly stalked foliage leaves are screw-shaped or opposite to alternate and are seldom composed simply or usually hand-shaped, the 1–9 leaflets or simple leaves are either entire or with a serrated edge. More or less developed, mostly sloping stipules may be present.

The species are mostly dioecious dioecious . The racemose or zymous to tufted or head-shaped inflorescences are usually axillary or rarely stem and leaf, the female flowers can also appear individually. The unisexual flowers are often threefold with a simple flower envelope , the petals are missing. The 3–9 sepals are mostly free and roof-top. There are 4 to over 20 mostly free stamens . A mostly lobed disc is usually present. Staminodes can occur in the female flowers, and a pestle in the male. The mostly upper, hairy to bald gynoeceum is mostly threefold, rarely two-digit and occasionally variable within the genera two- to five-fold. The styles are mostly free, rarely missing. The mostly undivided scars are pronounced and mostly simple, they can also be dry.

Each carpel contains two ovules with a pronounced nucellus , which are covered by a large obturator . The nucellus has a multi-layered tissue at its outermost end and is elongated, the process reaching into or up to the micropyle . This is formed by the inner and outer integuments , the inner one is usually thicker than the outer one.

The multi-seeded (1-6) fruits are opening or non-opening, stone or capsule-like, the seeds often have a seed callus .

Systematics and distribution

Petalostigma pubescens leaves
Foliage leaves and ripe fruits of Petalostigma triloculare

The Picrodendraceae family is tropical, with a focus on Australia (including New Guinea and New Caledonia), America and Africa (with Madagascar).

The flower structure as well as molecular genetic studies indicate a close relationship of the family to the Phyllanthaceae and the milkweed family in today's sense.

The family Picrodendraceae comprises around 28 genera with around 100 species and was separated from the former subfamily Oldfieldioideae of the milkweed family (Euphorbiaceae) in the course of molecular genetic results.

The approximately 28 genera of the Picrodendraceae family are:

  • Androstachys Prain : it contains only one species:
  • Aristogeitonia Prain : The seven or so species occur in tropical Africa and Madagascar.
  • Austrobuxus Miq. (Syn .: Canaca Guillaumin ): The approximately 22 species occur in the area from Malesia to the Fiji islands.
  • Choriceras Baill. : The only two species occur in New Guinea and Australia.
  • Croizatia Steyerm. : There are about five types (some authors also place them among the Phyllanthaceae).
  • Dissiliaria F. Muell. ex Baill. : The six or so species are only found in Queensland .
  • Hyaenanche Lamb. & Vahl : It only contains one type:
  • Kairothamnus Airy Shaw : It contains only one species:
  • Longetia Baill. : It contains only one type:
  • Micrantheum Desf. : The four or so species occur in Australia.
  • Mischodon Thwaites : It contains only one species:
  • Neoroepera Müll.Arg. & F.Muell. : It contains only one type:
  • Oldfieldia Benth. & Hook. : The four or so species occur in Africa.
  • Paradrypetes Kuhlm. (Some authors also put it to the Rhizophoraceae): The two species occur in Brazil.
  • Parodiodendron Hunz. : It contains only one type:
  • Petalostigma F. Muell. : The five or so species occur in New Guinea and Australia.
  • Picrodendron planch. : It contains only one type:
  • Piranhea Baill. : The four or so species are distributed from Mexico to Brazil.
  • Podocalyx Klotzsch : It contains only one species:
  • Pseudanthus Sieber ex Spreng. : The approximately nine species occur in Australia.
  • Sankowskya P.I. Forest . : It contains only one type:
  • Scagea McPherson : The only two species occur in New Caledonia.
  • Stachyandra J.-F.Leroy ex Radcl.-Sm. : The four or so species occur in Madagascar.
  • Stachystemon Planch. : The approximately nine species occur in Western Australia.
  • Tetracoccus Engelm. ex Parry : The four or so species occur in the USA and Mexico.
  • Voatamalo Capuron ex Bosser : The only two species occur in Madagascar.
  • Whyanbeelia Airy Shaw & B.Hyland : It contains only one species:

proof

  • D. Merino Sutter, PI Forster, PK Endress: Female flowers and systematic position of Picrodendraceae (Euphorbiaceae sl, Malpighiales). In: Plant Systematics and Evolution. Volume 261, 2006, pp. 187-215.

Individual evidence

  1. ↑ a b c P. F. Stevens: Angiosperm Phylogeny Website , Version 9, June 2008, online , accessed August 11, 2008.
  2. ↑ Rafaël Govaerts (ed.): Picodendraceae. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved January 22, 2015.

Web links

Commons : Picrodendraceae  - collection of images, videos and audio files