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''Banksia sessilis'', commonly known as parrot bush, is a species of shrub or tree in the plant genus ''Banksia'' in the Proteaceae family. It had been known as ''Dryandra sessilis'' until 2007, when the genus ''Dryandra'' was sunk into ''Banksia''. Widespread throughout southwest Western Australia, it is found on sandy soils over laterite or limestone, often as an understorey plant in open forest, woodland or shrubland. Encountered as a shrub or small tree up to 6 m (20 ft) in height, it has prickly dark green leaves and dome-shaped cream-yellow flowerheads. Flowering from winter through to late spring, it provides a key source of food—both the nectar and the insects it attracts—for honeyeaters in the cooler months, and species diversity is reduced in areas where there is little or no parrot bush occurring. Several species of honeyeater, some species of native bee, and the European honey bee seek out and consume the nectar, while the long-billed black cockatoo and Australian ringneck eat the seed. The life cycle of ''Banksia sessilis'' is adapted to regular bushfires. Killed by fire and regenerating by seed afterwards, each shrub generally produces many flowerheads and a massive amount of seed. It can recolonise disturbed areas, and may grow in thickets. ''Banksia sessilis'' has a somewhat complicated taxonomic history. It was collected from King George Sound in 1801 and described by Robert Brown in 1810 as ''Dryandra floribunda'', a name by which it was known for many years. However, Joseph Knight had published the name ''Josephia sessilis'' in 1809, which had precedence due to its earlier date, and the specific name was formalised in 1924. Four varieties are recognised. It is a prickly plant with little apparent horticultural potential, and none of the varieties are commonly seen in cultivation. A profuse producer of nectar, ''B. sessilis'' is valuable to the beekeeping industry. ==Description== ''Banksia sessilis'' grows as an upright shrub or small tree up to 6 m (20 ft) high, without a lignotuber. In most varieties, new stems are covered in soft, fine hairs that are lost with maturity; but new stems of ''B. sessilis'' var. ''flabellifolia'' are usually hairless. Leaves are blue-green or dark green. Their shape differs by variety: in var. ''cygnorum'' and var. ''flabellifolia'' they are wedge-shaped, with teeth only near the apex; in var. ''cordata'' they are wedge-shaped, but with teeth along the entire margin; and in var. ''sessilis'' they are somewhat broader at the base, sometimes almost oblong in shape. Leaf size ranges from 2 to 6 cm (1–2.5 in) in length, and 0.8–4 cm (0.3–1.6 in) in width. They may be sessile (that is, growing directly from the stem without a petiole) or on a petiole up to 0.5 cm (0.2 in) long. The inflorescences are cream or yellow, and occur in domed heads 4 to 5 cm (1½–2 in) wide, situated at the end of a stem. Each head contains from 55 to 125 individual flowers, surrounded at the base by a whorl of short involucral bracts. As with most other Proteaceae, individual flowers consist of a tubular perianth made up of four united tepals, and one long wiry style. The style end is initially trapped inside the upper perianth parts, but breaks free at anthesis. In ''B. sessilis'' the perianth is straight, 20 to 32 mm (0.8–1.3 in) long, and pale yellow. The style is slightly shorter, also straight, and cream-coloured. Thus in ''B. sessilis'', unlike many other ''Banksia'' species, the release of the style at anthesis does not result in a showy flower colour change.〔〔 One field study found that anthesis took place over four days, with the outer flowers opening first and moving inwards.〔 Flowering mostly takes place from July to November, although var. ''sessilis'' can start as early as May. After flowering, the flower parts wither and fall away, and up to four follicles develop in the receptable (the base of the flower head). Young follicles are covered in a fine fur, but this is lost as they mature. Mature follicles are ovoid in shape, and measure 1–1.5 cm (0.4–0.6 in) in length. Most follicles open as soon as they are ripe, revealing their contents: a woody seed separator and up to two winged seeds.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「banksia sessilis」の詳細全文を読む スポンサード リンク
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