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cone

cone

[kohn]
cone or strobilus, in botany, reproductive organ of the gymnosperms (the conifers, cycads, and ginkgoes). Like the flower in the angiosperms (flowering plants), the cone is actually a highly modified branch; unlike the flower, it does not have sepals or petals. Usually separate male (staminate, or pollen) cones and female (ovulate, or seed) cones are borne on the same plant. Each of the numerous scales, or sporophylls, of the staminate cone bears pollen and each female-cone scale bears ovules in which egg cells are produced. In the pine, a conifer, the staminate cones are small and short-lived; they are borne in clusters at the top of the tree. At the time of pollination, enormous numbers of pollen grains are released and dispersed by wind; those that land accidentally on female-cone scales extend pollen tubes part way into the ovule during one growing season but usually do not reach the stage of actual fertilization until the next year. The cones that are commonly observed are the seed cones, which are normally hard and woody although in a few the scales are fleshy at maturity. The terms strobili and cones are also applied to the comparable and nonseed bearing structures of the horsetails and club mosses.
cone or conical surface, in mathematics, surface generated by a moving line (the generator) that passes through a given fixed point (the vertex) and continually intersects a given fixed curve (the directrix). The generator creates two conical surfaces—one above and one below the vertex—called nappes. If the directing curve is a conic section (e.g., a circle or ellipse) the cone is called a quadric cone. The most common type of cone is the right circular cone, a quadric cone in which the directrix is a circle and the line drawn from the vertex to the center of the circle is perpendicular to the circle. The generator of a cone in any of its positions is called an element. The solid bounded by a conical surface and a plane (the base) whose intersection with the conical surface is a closed curve is also called a cone. The altitude of a cone is the perpendicular distance from its vertex to its base. The lateral area is the area of its conical surface. The volume is equal to one third the product of the altitude and the area of the base. The frustum of a cone is the portion of the cone between the base and a plane parallel to the base of the cone cutting the cone in two parts.
or ash cone

Deposit around a volcanic vent, formed by rock fragments or cinders that accumulate and gradually build a conical hill with a bowl-shaped crater at the top. Cinder cones develop from explosive eruptions of lavas and are often found along the flanks of shield (gently sloping) volcanoes. Lava flows may break out of the cone, or they may flow from under the cone through tunnels. Cinder cones are common in nearly all volcanic areas. Although they are composed of loose or only moderately consolidated cinder, many are surprisingly long-lasting, because rain falling on them sinks into the highly permeable cinders instead of running off down their slopes and eroding them.

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or strobilus

In botany, a mass of scales or bracts, usually ovate, containing the reproductive organs of certain non-flowering plants. A distinguishing feature of pines and other conifers, the cone is roughly analogous to the flower of other plants. Cones (strobili) are also found on club mosses and horsetails.

Learn more about cone with a free trial on Britannica.com.

A cone (from the Greek κῶνος, Latin conu) is a basic geometrical shape; see cone (geometry).

Cone may also refer to:

  • Conifer cone, a seed-bearing organ on conifer plants
  • Cone cell, in anatomy, a type of light-sensitive cell found along with rods in the retina of the eye
  • Cone snail, a carnivorous molluscs of the family Conidae
  • Elizabethan collar, a cone-shaped collar worn by pets
  • Ice cream cone, an edible container in which ice cream is served, shaped like an inverted cone open at its top
  • Pyrometric cone, in ceramic manufacture, a contolled mixture of minerals used to gauge the extent of firing
  • Traffic cone, a brightly colored cone-shaped plastic object commonly used as a temporary traffic barrier or warning sign
  • Skid cone, a cone like object place before a log in forestry
  • Volcanic cone, a mountain formed by material ejected from a volcanic vent
  • A type of optical fiber that tapers almost to a point
  • The part of a loudspeaker that moves the air, creating sound waves constantly
  • A colloquial Australian term for cannabis, most commonly a bong load or 'bowl' of cannabis
  • In cartography, a type of projection; see map projection

As a proper name:

In mathematics:

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