| Albizia | |
|---|---|
| Persian Silk Tree (Albizia julibrissin), foliage and blossoms |
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| Scientific classification | |
| Kingdom: | Plantae |
| (unranked): | Angiosperms |
| (unranked): | Eudicots |
| (unranked): | Rosids |
| Order: | Fabales |
| Family: | Fabaceae |
| Subfamily: | Mimosoideae |
| Tribe: | Ingeae |
| Genus: | Albizia Durazz., 1772 |
| Diversity | |
| About 150 species, see List of Albizia species | |
| Synonyms | |
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Albizzia Benth. |
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Albizia is a genus of about 150 species of mostly fast-growing subtropical and tropical trees and shrubs in the subfamily Mimosoideae of the legume family, Fabaceae. The genus is pantropical, occurring in Asia, Africa, Madagascar, Central, South, and southern North America and Australia, but mostly in the Old World tropics. Some species are considered weedy.
They are commonly called silk plant or sirises. Peculiarly, the obsolete form of spelling the generic name - with double 'z' - has stuck, so that another commonly used term is albizzias (though the form albizias is also found, particularly in species that are not widely known under a common name). The generic name refers to the Italian nobleman Filippo degli Albizzi, who in the mid-18th century introduced siris to Europe.
These are usually small trees or shrubs with a short lifespan - though the famous Samán del Guère near Maracay in Venezuela is a huge Albizia saman specimen and several hundred years old. The leaves are pinnately or bipinnately compound. Their small flowers are in bundles, with showy stamens much longer than the petals. Confusingly, some species are given the name "mimosa" which correctly belongs to species in the related genus Mimosa. Unlike those of Mimosa, Albizia flowers have much more than 10 stamens. Albizia can also be told apart from another large related genus, Acacia, since its flowers have their stamens joined at the base whereas in Acacia stamens are free (separated).[1]
Persian Silk Tree or Pink Siris (Albizia julibrissin) extends well north into temperate regions in East Asia and is by far the cold-hardiest species. It tolerates temperatures down to about −30 °C (−22 °F), provided it gets adequate summer heat to ripen the shoots. In North America it is commonly grown as an ornamental tree, but has become naturalized in several US states, and is regarded as an invasive species.
Albizia species are used as food plants by the larvae of some moths of the genus Endoclita inclulding E. damor, E. malabaricus and E. sericeus.
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Numerous species placed in Albizia by early authors were eventually moved to other genera, most notably Archidendron. Other genera of Ingeae (Abarema, Archidendropsis, Balizia, Blanchetiodendron, Calliandra, Cathormion, Enterolobium, Havardia, Hesperalbizia, Hydrochorea, Pararchidendron, Paraserianthes, Pseudosamanea and Serianthes) have also received their share of supposed Albizia species, as have the Mimoseae Newtonia and Schleinitzia, and Acacia from the Acacieae. Some presumed "silk trees" are in fact misidentified members of the not very closely related Erythrophleum from the Caesalpinioideae and the Faboideae Lebeckia.[2]
The delimitation of Falcataria and Pithecellobium, close relatives of Albizia, is notoriously complex, with species having been moved between the genera time and again, and probably will continue to do so. These include for example Falcataria moluccana (Moluccan Albizia, formerly Albizia moluccana), a common shade tree on tea plantations. Other closely related genera like Chloroleucon and Samanea are often merged with Albizia entirely.[2]
Molucca albizia (Falcataria moluccana) and Chinese albizia (Albizia chinensis) are considered invasive species in Hawaii and on many Pacific Islands.[3] The tree grows very rapidly and can quickly colonize disturbed areas in wet environments. The tree is prone to shedding large branches, which have been responsible for damaging power lines, houses, and other infrastructure in Hawaii.