A cone (in formal botanical usage: strobilus, plural strobili) is a reproductive organ found on plants belonging to the Pinophyta (conifers) division. The female cone, which produces seeds, is the well-known woody cone. Even at full maturity, male cones that release pollen are generally herbaceous and less noticeable. The word “cone” comes from the Greek word kosmos (pinecone), which was also the term given to the geometric cone. Scales are the individual plates that make up a cone.

All conifers have a substantially similar male cone (microstrobilus or pollen cone), with minor differences (mainly in scale arrangement) across species. Microsporophylls branch out from a central axis (modified leaves). One or more microsporangia can be seen beneath each microsporophyll (pollen sacs).

Ovules are contained in the female cone (megastrobilus, seed cone, or ovulation cone), which produce seeds when pollen fertilizes them. The female cone structure varies more dramatically between conifer families, and it is frequently critical for identifying many conifer species.

Pines, spruces, firs, cedars, larches, and other members of the pine family have imbricate cones (that is, with scales overlapping each other like fish scales). The “archetypal” tree cones are these pine cones, especially the woody female cones.

The female cone has two types of scales: bract scales and seed scales (or ovuliferous scales), each of which is generated from a highly modified branchlet and is subtended by each bract scale. Each seed scale has two ovules on the upper-side base that grow into seeds after pollen grains fertilize them. The bract scales appear initially and are visible during pollination; the seed scales appear later and surround and protect the seeds, with the bract scales seldom developing much further. The scales open briefly to receive gametophytes, close during fertilization and development, then reopen at maturity to let the seed escape. Most Pinaceae genera require 6″8 months to mature after pollination, although cedars take 12 months and most pines take 18″24 months (rarely longer). The seed scales stretch back when the cones dry up, or the cones disintegrate with the seed scales coming off (as in firs, cedars, and golden larch). The cones range in size from 2″60 cm long and 1″20 cm wide and are conic, cylindrical, or ovoid (egg-shaped).

The moisture level of non-serotinous pine cones determines when they open after ripening”cones open when dry and close when wet. This increases the distance traveled from the parent tree by ensuring that the tiny, windborne seeds are distributed during generally dry conditions. Even after seed distribution, a pine cone will go through numerous cycles of opening and shutting over its lifetime. This happens to elder cones while they’re still connected to branches and even after they’ve fallen to the forest floor. The state of fallen pine cones is a rough indicator of the moisture level of the forest floor, which is a key indicator of wildfire danger. Cones that are closed suggest moist conditions, whereas open cones indicate a dry forest floor.

As a result, people in temperate areas have long used pine cones to anticipate dry and wet weather, generally by suspending a harvested pine cone from a rope outdoors to assess air humidity.

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