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A conifer cone, or in formal botanical usage a strobilus, pl.: strobili, is a seed-bearing organ on gymnosperm plants, especially in conifers and cycads. They are usually woody and variously conic, cylindrical, ovoid, to globular, and have scales and bracts arranged around a central axis, but can be fleshy and berry-like.
Most conifers are monoecious, but some are subdioecious or dioecious; all are wind-pollinated. Conifer seeds develop inside a protective cone called a strobilus. The cones take from four months to three years to reach maturity, and vary in size from 2 to 600 millimetres (1 ⁄ 8 to 23 + 5 ⁄ 8 in) long.
This results in a scale like appearance. Two forms of woody cones act as the gametophyte structures, which mature approximately six months after pollination and are typically retained on the tree for up to one year. The female cones are spherical with pointed bract scales 12–15 mm in diameter. The male cones are much smaller 3–5 mm in diameter.
The male cones are small, 0.5–6 cm (1 ⁄ 4 – 2 + 1 ⁄ 4 in) long, and fall soon after pollination; pollen dispersal is by wind. Seed dispersal is mostly by wind, but some species have large seeds with reduced wings, and are dispersed by birds.
The pollen cones are 5–6 mm (0.20–0.24 in) long, produced on long spikes in early spring; they are produced only on trees growing in regions with hot summers. The cones are globose to ovoid, 1.5–2.5 cm (0.59–0.98 in) in diameter with 16–28 scales arranged in opposite pairs in four rows, each pair at right angles to the adjacent pair ...
Strobili are often called cones, but some botanists restrict the use of the term cone to the woody seed strobili of conifers. Strobili are characterized by a central axis (anatomically a stem ) surrounded by spirally arranged or decussate structures that may be modified leaves or modified stems .
Cross section of ovule in gymnosperms and angiosperms. Gymnosperm pollen is produced in microsporangia borne on the scales of the male cone or microstrobilus.In most species, the plants are wind-pollinated, and the pollen grains of conifers have air bladders that provide buoyancy in air currents.
The seed cones are ovoid-cylindric, 2 to 5 cm (3 ⁄ 4 to 2 in) long, with 40 to 80 seed scales; each scale bearing an exserted 4 to 8 mm (3 ⁄ 16 to 5 ⁄ 16 in) bract. The cones are green [ 5 ] to reddish purple when immature, turning brown and the scales opening flat or reflexed to release the seeds when mature, four to six months after ...