• Source: Abrotanella

Abrotanella is a genus in the family Asteraceae, of 23 species, native to Australia, New Zealand and southern South America.
They are usually small plants, sometimes not reaching more than a few millimetres above the ground, although some form cushions in bolster heaths reaching up to a metre in diameter.




Taxonomy


Genus Abrotanella is placed in the tribe Senecioneae and is the sole genus in the subtribe Abrotanellinae. The genus was formerly placed in the subtribe Blennospermatinae, but molecular and morphological studies have shown it to be distinct from other genera in that group.
Phylogenetic studies have shown that Abrotanella forms a well-supported monophyletic group. It is sister to a clade formed by three other genera: Crocidium, Blennosperma, and Ischnea. Within Abrotanella, A. forsteroides from Tasmania is sister to all other species in the genus.




Evolutionary history


The evolutionary history of Abrotanella has been investigated using molecular dating techniques, providing insights into the timing of its diversification. According to these studies, the stem age of Abrotanella is estimated to be approximately 19.4 million years ago, placing its origin in the early Miocene. However, the radiation of extant species began much later, around 4.2 million years ago during the Pliocene. This was followed by a significant divergence event about 3.1 million years ago, which led to the formation of the two main lineages observed within the genus.
Biogeographic analyses suggest that South America was likely part of the ancestral area for Abrotanella. The genus is thought to have reached New Zealand and other Pacific areas through long-distance dispersal, as the timing of its evolution postdates the separation of these landmasses. This finding challenges earlier hypotheses that might have attributed the distribution of Abrotanella to ancient vicariance events related to the break-up of Gondwana.
The distribution of Abrotanella species reflects a complex history involving both vicariance and dispersal events. Researchers have proposed that this distribution pattern may have resulted from a combination of factors, including potential migration via land bridges or stepping stones along the Antarctic coast, as well as long-distance dispersal across ocean barriers.




Description


Abrotanella comprises small alpine or subalpine plants, often forming cushions. They are typically found growing in moist habitats, herbfields, among rocks, or on bare soils.
Most species of Abrotanella lack obvious adaptations for long-distance dispersal. However, some species, such as A. submarginata and A. muscosa, have fruits with twin hairs and an apical crown, which could potentially aid in dispersal.

Species

Synonyms
Abrotanella crassipes Skottsb. is synonym of Abrotanella linearifolia A.Gray
Abrotanella filiformis Petrie is synonym of Abrotanella linearis Bergg.
Rhamphogyne rhynchocarpa was formerly placed here with the name Abrotanella rhynchocarpa




References






Bibliography






External links


"Genus Abrotanella". UniProt Consortium. Retrieved 2008-04-15.
Data related to Abrotanella at Wikispecies

Kata Kunci Pencarian:

• Daftar genera Asteraceae
• Abrotanella
• Abrotanella scapigera
• Abrotanella forsteroides
• Abrotanella rostrata
• Abrotanella rosulata
• Abrotanella trilobata
• Abrotanella fertilis
• Abrotanella caespitosa
• Abrotanella nivigena
• Abrotanella emarginata