Didiereaceae

Didierea madagascariensis

The Didiereaceae is a family in the order of the clove -like ( Caryophyllales ) within the angiosperms. While the family in the old scope with four genera found only on Madagascar are located in the capensis and eastern Africa, the newly added three genera. Few species are used as ornamental plants.

  • 3.1 Outer systematics
  • 3.2 Internal systematics
  • 4.1 Literature
  • 4.2 Notes and references

Description

Vegetative characteristics

They are succulent, thick-stemmed shrubs or trees, often with cactus -like growth form, sometimes with a juvenile stage with rampant, trailing branches before a dominant strain is formed. The branches are initially long shoots in their axils develop short shoots. The leaves appear along with tapered to needle-like spines of areoles, which are sometimes spirally arranged warts. Portulacarioideae are not reinforced. The leaves of the long shoots are usually small and frail, the decussate standing leaves of short shoots keep one growing season. Since the branches are green, the plants can even in the leafless state photosynthesis operate (all species with CAM mechanism ).

Generative features

The inflorescences formed from the areoles branch forked or doldenartig. Calyptrotheca and Portulacaria have only hermaphrodite flowers, female and hermaphrodite flowers Decarya own. For all other genera are unisexual and dioecious species getrenntgeschlechtig ( dioecious ) in Decarya female- dioecious. The relatively small flowers have a double perianth. The only two sepals are free and often unequal. The Didiereoideae at four in the other subfamilies five petals are usually free or fused at Portulacaria. The male flowers contain at Didiereoideae two circles, each with four or five at Ceraria a circle with five free stamens in Portulacaria usually four to seven, rarely up to ten intergrown with the perianth stamens in Calyptrotheca many free stamens and a rudiment of the ovary. In the female flowers three rarely two or four carpels become an above -earth, unilocular ovary are usually grown with a long pen, of the three, rarely two or four-lobed stigma usually ends in.

Dry and more or less triangular capsule fruit is encased in the pair of persistent sepals and contains only one seed.

The number of chromosomes in the Didiereoideae be 2n = 48, 192, 240, in the Calyptrothecoideae they are not known and the Portulacarioideae 2n = 44, 48, 72

Dissemination

Only the Didieroideae, not the family of Didiereaceae is endemic to Madagascar. They grow in seasonally very dry thorn forests in the south and southwest of the island. The other three genera are native to the capensis and eastern Africa.

Some species are cultivated as ornamentals. The most common representative in collections of succulent plants is the bacon tree, money tree, penny tree, elephant tree, Strauchportulak, Jadebaum ( Portulacaria afra ), represented much less is Alluaudia procera.

System

Outer systematics

It turned out molecular genetic studies show that the Portulacaceae were paraphyletic and s.str in a common clade with the Didiereaceae. stood together and result in a monophyletic family. Within the order of Caryophyllales the Didiereaceae are close to the Halophytaceae, Basellaceae, Montiaceae and the clade of Talinaceae, Portulacaceae, Anacampserotaceae and Cactaceae.

Relatively closely related are the Didiereaceae with the cactus family ( Cactaceae ). With these, the Didiereaceae share the particularity to possess areoles. Therefore, the Didiereaceae are sometimes called the " Cacti of the Old World ." Plants of Didiereaceae can also be grafted on plants of the more original cacti genera Pereskia and Pereskiopsis.

Also closely related are the Portulakgewächse ( Portulacaceae ). According to the research by Wendy L. Applequist and Robert S. Wallace 2001, 2003 was proposed because of the very close relationship of the African species Calyptrotheca, Ceraria and Portulacaria these to be among the Didiereaceae.

Inside systematics

The valid first publication of the family name Didiereaceae was in 1896 by Ludwig Adolph Timotheus Radlkofer in The natural plant families, 3 ( 5), p 462; the publication of Emmanuel Drake del Castillo in Bull Mus. Hist. Nat. (Paris), 9, 36 took place only in 1903. The type genus is Didierea Baill ..

Previously there was a family of four genera with a total of eleven species.

Currently, the family is divided into three subfamilies, which includes the following seven genera:

  • Calyptrothecoideae Appleq. & R.S.Wallace, with only one genus: Calyptrotheca Gilg: With two species from tropical East Africa: Calyptrotheca somalensis Gilg
  • Calyptrotheca taitense ( Pax & Vatke ) Brenan
  • Ceraria Pearson & Stephens
  • Portulacaria Jacq. Using two species in Capensis and in Kenya: Portulacaria afra Jacq.
  • Alluaudia ( Drake ) Drake
  • Alluaudiopsis Humbert & Choux: With two ways: Alluaudiopsis fiherensis Humbert & Choux
  • Alluaudiopsis marnieriana roughness
  • Decarya madagascariensis Choux
  • Didierea madagascariensis Baill.
  • Didierea trollii Capuron & Rauh

Swell

  • The Didiereaceae in APWebsite family. (English )
  • The Didiereaceae in the old scope at DELTA family. (English )
  • Wendy L. Applequist, Robert S. Wallace: Expanded circumscription of Didiereaceae and its division into three subfamilies. In: Adansonia Episode 3, Volume 25, Number 1, 2003, pp. 13-16 (pdf, 82 kB).
Crassulacean acid metabolism Umbel Vestigiality Ovary (botany) Stigma (botany) Alluaudia montagnacii Alluaudia ascendens Werner Rauh
289917
de