Rapateaceae

Stegolepis guianensis on Roraima Tepui in Venezuela

The Rapateaceae are a family of plants that belongs to the order Süßgrasartigen ( Poales ). It contains 16 to 17 species with about 80 to about 94 species. With the exception of a species are all neotropisch common.

• 3.1 Notes and references

Description

Habit and foliage leaves

The types of Rapateaceae are usually coarse, perennial herbaceous plants with rhizomes. They rarely grow as epiphytes, mostly terrestrial often in nutrient-poor soils.

The leaves are alternate, usually arranged in three lines or spirals and rosettes at the base of the plant. The leaves are in leaf sheath, petiole (eg Saxofridericia ) and leaf blade broken or it lacks a petiole. The leaf sheath is open. The simple leaf blade is flat or folded (usually v -shaped) or pencil -shaped, parallel-veined and entire. The leaf blade is often rotated by 90 ° and can be significantly asymmetric, then the median nerve is clearly shifted to one side. The stomata are paracytisch.

Inflorescences and flowers

Side are constantly being formed are usually very long, leafless Blütenstandsschäfte; at Maschalocephalus they are greatly reduced. In capitate to einseitswendigen racemose inflorescences total are rarely a part of inflorescence, but usually summarized many eared or Rispige part inflorescences with many flowers. The partial inflorescences rarely have only one, usually two bracts, which can sometimes be grown; they are usually large and wide at their base and rarely encase the part inflorescences completely. The partial inflorescences act more or less as Pseudanthium with a kind of spathe. Under each one to several flower bracts are present.

The hermaphrodite flowers are radial symmetry to slightly zygomorphic and threefold with double perianth. The three sepals are sometimes fused at the base. The three delicate petals are mostly grown Roehrig at their base and are not long lasting; they are mostly yellow or sometimes red and sometimes have a brown to violet drawing. The flowers contain two circles, each with three fertile stamens. The filaments free or fused together at the base and are fused in some species the petals. The anthers open by pores. Three carpels are fused into a superior ovaries. In each of the three ovary chambers anatrope or two or five to fifty ovules are present. In Spathanthus the three ovary chambers is only one fertile. The style ends in a simple, capitate stigma. Pollination is by insects ( entomophily ) or birds ( Ornithophilie ).

Fruit and seeds

Are formed lokulizide capsule fruits. The winged or wingless seeds contain a small ( rudimentary at seed maturity ) embryo and a well-developed endosperm with some strength.

Ingredients and chromosome number

In the epidermis, several more or less drusige silica bodies and tannin brown cells are present in cells. All types accumulate aluminum usually in larger amounts only a few species in small doses; this is otherwise in monocots rare. There are mucilage cells present.

The chromosome number, for example at Maschalocephalus is 2n = 22

Systematics and distribution

The Rapateaceae occur with one exception only in the Neotropics. They thrive in the tropical to subtropical climates. Most species are native to the tropical eastern South America, some species extend to Bolivia and Panama. The center of diversity is the Guiana Shield in lowland areas on the tepuis. Paläotropisch only the African genus Maschalocephalus with the way Maschalocephalus is dinklagei in tropical West Africa in Sierra Leone and Liberia; it has passed through remote spread there. The origin of the family is at 112 million years dated before today with an Adaptive Radiation approximately 65 million years ago.

The family name Rapateaceae was published in 1829 by Barthélemy Charles Joseph Dumortier in analysis of Familles de Plantes, 60, 62. Type genus is Rapatea Aubl.

There are 16 to 17 genera, seven of which are monotypic, with a total of about 80 to 94 species in this family. It is divided into three subfamilies:

• Rapateoideae Maguire: With three genera and 29 species. Cephalostemon R.H.Schomb. With about five species.
• Rapatea Aubl. With about 21 species. It has the widest distribution of all genera within the family from northern South America to Peru.
• Spathanthus Desv. With only two species.

• Maschalocephalus Gilg & K.Schum. With the only kind: Maschalocephalus dinklagei Gilg & K.Schum: . These only West African species grows in moist forests and sandy savannas in Sierra Leone and Liberia.

• Potarophytum riparium Sandwith: It thrives on the Kaieteur plateau of the Guyana Shield.

• Windsorina guianensis Gleason: It thrives in the Kaieteur gorge on the Guyana Shield.

• Amphiphyllum Gleason, with only one type: Amphiphyllum rigidum Gleason: It is endemic to the Cerro Duida in southern Venezuela.

• Guacamaya superba Maguire: Widespread on the Guiana Shield.

• Marahuacaea schomburgkii ( Maguire ) Maguire: It is endemic to the Cerro Makahuaka in southern Venezuela.

• Phelpsiella ptericaulis Maguire: It is endemic to the Cerro Paru in Venezuela.

Swell

• The Rapateaceae in APWebsite family. (Section Description and systematics)
• L.Watson and MJDallwitz: The Rapateaceae at DELTA family. ( Description section )
• Thomas J. Givnish, Kendra C. Millam, Timothy M. Evans, Jocelyn C. Hall, J. Chris Pires, Paul E. Berry, Kenneth J. Sytsma: Ancient Vicariance or Recent Long -Distance Dispersal? Inferences about phylogeny and South American - African Disjunctions in Rapateaceae and Bromeliaceae based on ndhF Sequence Data, in: International Journal of Plant Sciences, Volume 165, 2004, Supplement, pp. 35-54: Online. ( Section systematics, PDF, 1.4 MB)
• Darren M. Crayn, J. Andrew C. Smith & Klaus Winter: Carbon Isotope Ratios and Photosynthetic Pathways in the Neotropical Family Rapateaceae in Plant Biology, Volume 3, No. 5, 2001, pp. 569-576: Online. (PDF; 191 kB)
• David John Mabberley: The Plant-Book. A portable dictionary of the higher plants. Cambridge University Press 1987. ISBN 0-521-34060-8