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Populus

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The genus *Populus* contains many different species of deciduous flowering plants.

Four Poplars in four seasons
Four Poplars in four seasons

These plants belong to the Salicaceae family and live mostly in the Northern Hemisphere. You may know them by names like aspen, poplar, or cottonwood. Currently, there are 57 accepted species within this genus. These trees are important because they grow very quickly and have high genetic diversity. They can grow to be quite tall with very large trunks.

Populier mannelijke bloeiwijze (Populus canadensis male inflorescences)
Populier mannelijke bloeiwijze (Populus canadensis male inflorescences)

Scientists study them to understand how plants evolve and adapt to different environments.

Poplar trees have several unique physical features. The bark on young trees is often smooth and white, green, or dark grey. These young trees frequently have conspicuous lenticels, which are small pores on the surface. As the trees age, some species keep their smooth bark. Other species develop bark that is rough and deeply fissured. The shoots of these trees are stout and always have a terminal bud at the end. This is a key difference between poplars and their relatives, the willows.

Populus lasiocarpa leaves 01 by Line1
Populus lasiocarpa leaves 01 by Line1

The leaves are arranged spirally around the stems. They can be triangular, circular, or even lobed in some cases.

A fascinating mechanism involves how the leaves move in the wind. In certain sections, like *Populus* and *Aigeiros*, the petioles are laterally flattened. A petiole is the stalk that joins a leaf to the stem. Because these stalks are flat, even a light breeze causes the leaves to wobble. This movement gives the entire tree a "twinkling" appearance. The size of the leaves can vary greatly on a single tree. Leaves on side shoots are typically small, while leaves on strong lead shoots are very large. In the autumn, these leaves often turn bright gold or yellow before they fall.

Reproduction in *Populus* involves a specific process using wind. Most species are dioecious, meaning male and female flowers are on separate plants. These flowers appear as long, drooping catkins in the early spring. The catkins grow from buds formed in the leaf axils during the previous year. Male flowers have between four and 60 stamens. These stamens have short, pale yellow filaments and colorful anthers. Female flowers contain a single-celled ovary with several ovules.

Populus (Populier zaadpluis en zaden)1
Populus (Populier zaadpluis en zaden)1

After pollination by the wind, the female catkins grow much longer. The fruit is a capsule that opens in midsummer to release seeds. Each tiny seed is surrounded by soft, white hairs that help the wind carry them away.

Historically, scientists have used *Populus* to learn about plant evolution. In 2006, the western balsam poplar (*P. trichocarpa*) became a major milestone. It was the first tree to have its entire DNA code determined through DNA sequencing. Researchers also study fossils to trace the history of the genus. They have found *Populus wilmattae* fossils from the Late Paleocene, about 58 million years ago. Fossils from the Cretaceous period have also been discovered in Tibet and China. These findings help us understand how the genus has changed over millions of years.

Humans use *Populus* for many different purposes today.

The wood is light and porous, making it flexible with a close grain. This makes it useful for manufacturing paper and pulpwood. It is also used for making plywood. In India, farmers in the Punjab region grow varieties like G48 and w22 commercially. In Pakistan, farmers grow poplars, though they must watch for termite attacks. The wood is even used as bait in termite traps for biocontrol.

Pamirihouse
Pamirihouse

Historically, the Greeks and Etruscans even used poplar wood to make shields.

*Populus* species are also deeply connected to local ecosystems. They serve as important food plants for the larvae of many Lepidoptera species. Some mushrooms, like the aspen oyster mushroom, live only on dead *Populus* wood. Some trees can also form massive colonies through a process called suckering. A famous example is the Pando forest, which consists of thousands of *Populus tremuloides* clones. While they are useful, people must be careful when planting them near buildings. Their vigorous root systems can grow up to 100 feet and may damage foundations or water pipes.

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🖼️ Images & Media (12)
File:Trembling Aspen.jpg
Trembling Aspen.jpg
File:Populier mannelijke bloeiwijze (Populus canadensis male inflorescences).jpg
Populier mannelijke bloeiwijze (Populus...
File:Populus (Populier zaadpluis en zaden)1.jpg
Populus (Populier zaadpluis en zaden)1.jpg
File:Four Poplars in four seasons.JPG
Four Poplars in four seasons.JPG
File:PopulusNigra3.jpg
PopulusNigra3.jpg
File:Heinolan tsaarinpoppeli.jpg
Heinolan tsaarinpoppeli.jpg
File:Populus lasiocarpa leaves 01 by Line1.JPG
Populus lasiocarpa leaves 01 by Line1.JPG
File:Populus nigra-bekes.jpg
Populus nigra-bekes.jpg
File:Poplars of Khorog City Park.JPG
Poplars of Khorog City Park.JPG
File:KDJHPOP.JPG
KDJHPOP.JPG
File:Pamirihouse.JPG
Pamirihouse.JPG
File:Rotor poplar and willow cuttings planter, planting a new nursery of poplar for biomass with short rotation..JPG
Rotor poplar and willow cuttings planter,...
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