The Strelitziaceae (Strelitziaceae) are a plant family in the order of ginger-type (Zingiberals). This family contains only three genera of seven species. Some species are used as ornamental plants .
Description and ecology
Appearance and leaves
They are perennial , herbaceous plants that are sometimes very large. They form short branched rhizomes . The above-ground stems are usually unbranched or rarely dichotomous branches. Often many plants are horstartig together. An exception within the order of the Zingiberals are the woody stem axons at Phenakospermum and Ravenala . A secondary growth in thickness is missing, therefore one speaks with the ” tree of the travelers ” botanically also of tree-shaped plant and not of tree.
The alternate and two-rowed leaves are divided into leaf sheath, petiole and leaf blade. The long, simple leaf blades have a prominent midrib and almost parallel, but slightly sigmoid, ie weakly S-shaped lateral nerves that meet near the smooth leaf margin. As with the sister group of the banana family (Musaceae) and as with the flower tube plants (Cannaceae), the leaves show convolute Vernation (rolled bud position). There are no ligules.
Inflorescences and flowers
Inflorescence of the bird of paradise flower ( Strelitzia reginae )
Blue hairy Arillus of seeds in cracked capsules of Ravenala madagascariensis
The lateral or terminal inflorescences (inflorescences) are winding and have boat-shaped, green bracts (bracts) that use the pollinating birds to sit.
The hermaphrodite flowers are zygomorphic and threefold. There are two circles, each with three blossom bracts. The three free bracts of the outer circle are the same or different. Of the three inflorescences of the inner circle, the two lateral ones form an arrow-like covering around the stylus, and in Strelitzia also the stamens. There are originally two circles, each with three fertile stamens present. In Ravenala all six stamens are present, but in all other species one of the inner circle is missing. Unlike many other families of the order are no stamens staminodestransformed. The two-celled pollen grains have no aperture and they largely lack an exine, but they have a thick intestine. Three carpels are one under constant ovary intergrown, continuous central angle with many (20 to 50) ovules in each of the three chambers ovary; he has an extension, which forms a solid tube. Deeply sunken septal nectaries are present in the ovary wall . The style ends in a simple or trilobed scar. Most species are pollinated by birds ( ornithophilia ), Phenakospermum of bats ( Chiropterophilia ),Ravenala of lemurs .
Fruits and seeds
They form woody, loculicidal capsule fruits .
The seeds always have a starchy endosperm and always an aril. The striking, brightly colored (in Ravenala blue, in Strelitzia orange, in red Phenakospermum ) Arillus is lumpy lobed or heavily hairy. The spread of the seeds is usually done by birds.
Ingredients and Chromosome Sets
In the mesophyll are calcium oxalate crystals embedded as raphides. Strength is stored in the seeds and rhizomes.
The basic chromosome numbers are n = rarely 7 or 9, usually 11; For example, chromosome numbers of 2n = 14 or 2n = 22 were determined.
Few species are used as ornamental plants throughout the tropical belt .
Distribution map , which reproduces the distribution area of the genera only vaguely, since for Phenakospermum the area is too small and for the other two genera too large
Systematics and distribution
The distribution areas are the tropical South America (only Phenakospermum ), the eastern South Africa (only Strelitzia ), Madeira and Madagascar (only Ravenala ).
In 1900, Karl Moritz Schumann first established a subfamily Strelitzioideae within the Musaceae. It was placed in 1934 by John Hutchinson in The Families of Flowering Plants , Volume 2, p. 72 in the rank of a family of Strelitziaceae. Type genus is Strelitzia Ait. The botanical genus name Strelitzia honors Princess Charlotte of Mecklenburg-Strelitz (1744-1818), the wife of the English King George III.
According to molecular biological studies, the Strelitziaceae are the sister family of the Lowiaceae and closely related to the families Heliconiaceae and Musaceae .
The family contains three genera, two of which are monotypic , with a total of seven species:
Habitus and inflorescences of Strelitzia juncea
Inflorescence of Strelitzia nicolai
Strelitzia ( Strelitzia Ait. ): The five species are distributed along the eastern coast of South Africa:
White Strelitzia ( Strelitzia alba (L. f.) Skeels , Syn: Strelitzia angusta Thunb. ): It occurs in South Africa from the district of Knysna in the Western Cape Province to the district of Humansdorp in the Eastern Cape .
Mountain Strelitzia ( Strelitzia caudata R.A.Dyer ): It is distributed in southern Africa from Limpopo , Mpumalanga and Swaziland to the eastern highlands of Zimbabwe .
Natal or Tree Strelitzia ( Strelitzia nicolai Rule & Koern. ): It is distributed in South Africa from south East London in the Eastern Cape to KwaZulu-Natal on to Mozambique and Zimbabwe .
Strelitzia juncea Link : This endemic occurs in South Africa only near Uitenhage , Patensie and just north of Port Elizabeth in the Eastern Cape.
Bird of Paradise or King Strelitzia ( Strelitzia reginae Aiton ): It occurs in two subspecies only in the South African provinces of Eastern Cape and KwaZulu-Natal. It is used in tropical parks and gardens as an ornamental plant, as a container plant in non-tropical countries and as a long-lasting cut flower .
Ravenala Adans. : It contains only one kind:
Tree of travelers ( Ravenala madagascariensis Sonn. ): The original distribution area is located in eastern Madagascar at altitudes below 1000 meters. It is planted in parks throughout the tropics as an ornamental plant. He becomes very tall and forms a trunk.
Phenakospermum Endl. : It contains only one species. It is reported by a second species: Phenakospermum amazonicum (Mart.) Miq. , she was even placed in a separate genus Musidendron Nikai . Today this is only synonymous with Phenakospermum guyannense :
Phenakospermum guyannense (LCRich.) Endl. ex Miq. It iswidespreadthroughout the Amazon basin , in tropical northern and central South America east of the Andes . It reaches heights of growth of 2 to 5 meters and looks similar to the “tree of the travelers”, but possesses only a pseudo trunk similar to that of the bananas .