Proteales | plant order | Britannica

Proteales | plant order | Britannica

Proteales, the protea order of dicotyledonous flowering crops, with three households, round 75 genera, and almost 1,060 species. Together with Buxales, Ranunculales, Trochodendrales, and Sabiaceae, Proteales is a part of a bunch often known as peripheral eudicots within the Angiosperm Phylogeny Group III (APG III) botanical classification system (see angiosperm).

The most important household within the order is Proteaceae, which has near 75 genera and 1,050 species and is confined predominantly to the Southern Hemisphere, largely in Australia, South Africa, and Madagascar. Platanaceae has a single Northern Hemisphere genus Platanus, with 8–10 species. Equally, Nelumbonaceae has only one aquatic genus, Nelumbo (lotus), with two north-temperate species. The reassignment of those households right into a single order was a stunning consequence of family-level molecular research. It’s laborious to think about three such disparate households being grouped right into a single order, however even nonmolecular knowledge supply some assist for this relationship, significantly the connection of Platanus and Proteaceae.

Members of Proteaceae are woody bushes and shrubs. The crops are characterised by flowers which are often individually small however are mixed into dense, typically showy inflorescences (floral clusters). They’ve a four-parted perianth (whorl of petal-like elements), with the 4 stamens (male pollen-producing constructions) joined to the guidelines of the perianth segments, generally with solely the anther (pollen sac) seen. The easy or generally much-divided leaves are often alternately organized and are sometimes densely lined with hairs or have a thick cuticle, and the stomata in some species are restricted to deep pits with occluded entrances. Some or all of those traits could also be diversifications to assist retard water loss. The crops sometimes develop in areas which have an extended dry season every year. Even distantly associated family members might exhibit related diversifications to fireside, specifically huge underground woody tubers or seeds held in woody follicles which are launched solely after a burn.

The most important genera of Proteaceae are Grevillea (together with Hakea), Protea, Banksia, Helicia, Leucadendron, and Persoonia. Australia has the best variety of genera within the household, with 45 (35 of them endemic, or solely discovered there). South Africa has 14 genera (11 endemic), and New Caledonia has 9 genera (6 endemic). Jap Malesia and New Guinea collectively have Eight genera (none endemic), and South America has Eight genera (four endemic).

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In heat areas, a number of species of Proteaceae are cultivated as ornamentals, together with Leucadendron argenteum (silver tree), the leaves of that are lined with nice silky hairs; totally different species of Banksia (Australian honeysuckles); members of Embothrium (hearth bushes, or hearth bushes); and members of Grevillea. Grevillea robusta (silky oak), native to Australia, is extensively grown in heat climates. Macadamia integrifolia (macadamia) is grown for its edible seeds.

Platanus is the genus of aircraft bushes, sycamores, and buttonwood. These are deciduous bushes of the Northern Hemisphere, with gentle scaly bark and palmately-lobed leaves. The flowers are small and grouped collectively in dense, unisexual, wind-pollinated heads that dangle on skinny stems. Platanus occidentalis is the American sycamore, and P. orientalis is the Oriental aircraft tree; the 2 species have been hybridized, and lots of the cultivated aircraft bushes could also be of hybrid origin.

Two species of lotus, the sacred lotus (Nelumbo nucifera) and the American lotus (Nelumbo lutea), are the only real members of the aquatic household Nelumbonaceae. These water crops are simply acknowledged by their giant spherical leaves, that are held above the water floor like inverted umbrellas, and by their flowers, that are much like these of water lilies however have free carpels immersed in a big obconical (inverted cone form) receptacle. The seeds have an especially laborious masking and may stay viable for hundreds of years in river mud. The household bears a superficial resemblance however a distant relationship to the water lilies (household Nymphaeaceae), the place they have been previously included.

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