Acaena
Acaena caesiiglauca, leaves and inflorescences
The Stachelnüsschen ( Acaena ) are a genus of the subfamily Rosoideae within the rose family ( Rosaceae ). The genus includes 55-60 species that are mainly distributed in the southern hemisphere.
- 8.1 Notes and references
Description
Vegetative characteristics
Acaena species are mostly evergreen, perennial herbaceous plants or rarely subshrubs and reach stature heights of 0.2 to 0.6 meters. The arranged in basal rosettes or alternate distributed on the stem leaves are divided into petiole and leaf blade. The leaf blade is pinnate 4-15 cm long and unpaired. The 7-25 leaflets are often lobed and serrated to the Endfiederblättchen is usually greatest. The leaves are hairy. The two stipules are mutually free but adherent to the petiole.
Generative features
The inconspicuous, sessile flowers form a mostly dense, spherical inflorescence with a diameter of 1-2 cm with bracts. The small, hermaphroditic flowers are radial symmetry and four or fünfzählig. Most four sepals are present. The flowers contain petals ( petals ). There are two to ten stamens present. The carpels are free. The fruit stands are usually conspicuous, capitula -shaped and often stachelborstig. Thus, the seeds of many species can be velcro -like baste in fur or feathers, and are spread over long distances. Pollen is carried by wind.
Dissemination
Acaena species are mainly located in the southern hemisphere, especially in South America, New Zealand and Australia. However, some species are also found in the northern hemisphere, such as the endemic Hawaiian species Acaena exigua or Acaena pinnatifida, grows both in California and in southern South America.
Ecological problem types
Some species were often abducted by tack welded to sheep wool seeds, in areas outside of their home, and established themselves there as neophytes partly aggressive character. Acaena novae- zelandiae ( to New Zealand as " Bidibib " or " Biddy biddy " means, derived from the Maori name " Piripiri " ) has been spreading in the UK and is now commonly found there in coastal dunes, where it displaces native vegetation and, moreover, makes uncomfortable with his spiky fruits noticeable at the feet of bathers.
Taxonomy
The first description of the genus Acaena was published in 1771 by Carl Linnaeus. The only way it treated and thus the type species is Acaena elongata. The description was based on a manuscript of the Spanish botanist José Mutis. Linnaeus gave Mexico as the country of origin of the underlying Aufsammlungsmaterials, but in fact this came from Colombia. Ancistrum J.R.Forst. & G.Forst. is a synonym.
Species
The German botanist Georg Bitter has distinguished 110 species in the last full revision of the genus. Since then, many of the distinguished him to species rank taxa have been placed as synonyms to other species, especially regarding Acaena magellanica. The following list of species is therefore based largely on recent regional species lists or floras area.
Gallery
Acaena cylindristachya
Acaena elongata
Acaena magellanica
Acaena novae- zelandiae
Acaena ovalifolia
Acaena pinnatifida
Acaena sericea
Use
Because of their partially decorative, colorful fruit stands and their suitability as a fast-growing ground cover, some species are cultivated. You are in Central Europe, however, only partially hardy.
Swell
- Marticorena A. 2006: Revisión del género Acaena ( Rosaceae ) en Chile. Annals of the Missouri Botanical Garden 93: 412-454. - Online
- Amanda Spooner: Acaena in the Western Australian Flora, 2008.