Populus sect. Aigeiros
Populus sect. Aigeiros | |
---|---|
Populus fremontii in fall color | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Malpighiales |
Family: | Salicaceae |
Genus: | Populus |
Section: | Populus sect. Aigeiros Duby[1] |
Type species | |
Populus nigra L.
| |
Species | |
Populus section Aigeiros is a section of three species in the genus Populus, the poplars. Like some other species in the genus Populus, they are commonly known as cottonwoods. The species are native to North America, Europe, and western Asia. In the past, as many as six species were recognized, but recent trends have been to accept just three species, treating the others as subspecies of P. deltoides.
They are large, deciduous trees that are 15–30 m (50–100 ft) tall and diameters of 4 m (13 ft),[2] distinguished by thick, deeply fissured bark and triangular-based to diamond-shaped leaves that are green on both sides (without the whitish wax on the undersides) and without any obvious balsam scent in spring. An important feature of the leaves is the petiole, which is flattened sideways so that the leaves have a particular type of movement in the wind.
Male and female flowers are in separate catkins, appearing before the leaves in spring. The seeds are borne on cottony structures that allow them to be blown long distances in the air before settling to ground.
The cottonwoods are exceptionally tolerant of flooding, erosion, and flood deposits filling around the trunk.
Although each of the three cottonwood species has a different leaf pattern, they all have the same general diamond leaf shape.
Species
Populus deltoides
Eastern cottonwood (Populus deltoides) is one of the largest North American hardwood trees, although the wood is rather soft. It is a riparian zone tree. It occurs throughout the eastern United States, parts of southern Canada, and northern Mexico. The leaves are alternate and simple, with coarsely toothed (crenate/serrate) edges, and subcordate at the base. The leaf shape is roughly triangular, hence the species name, deltoides. Their winter buds are enrobed in a protective, fragrant resin that coats young leaves when they unfurl from the bud.
In the typical subspecies P. d. deltoides (
, the subspecies P. d. wislizeni (Rio Grande cottonwood; syn. P. wislizeni) occurs.Populus fremontii
Populus nigra
Black poplar (P. nigra) is native to Europe and Western Asia, is distinct in its much smaller leaves, 5–11 cm (2.0–4.3 in) across, with a more rhombic (diamond) shape.
Cultivation and uses
Cottonwoods are widely grown for
Cottonwood bark is often a favorite medium for artisans. The bark, which is usually harvested in the fall after a tree's death, is generally very soft and easy to carve.
Cottonwood is one of the poorest wood fuels; it does not dry well, and rots quickly. It splits poorly, because it is very fibrous. It produces a low level of energy per unit of volume of wood.[8]
Cottonwoods serve as food for the caterpillars of several Lepidoptera.
References
- ^ de Candolle, Augustin Pyramus; Duby, Jean Étienne (1828). "Botanicon Gallicum; seu, Synopsis plantarum in flora Gallica descriptarum" (second ed.). Desray, Paris. p. 427.
- ^ Isebrands, Jud G.; Richardson, Jim (February 12, 2014). "Poplars and Willows: Trees for Society and the Environment". CABI – via Google Books.
- ^ "Populus fremontii (Fremont cottonwood)". Calflora Database.
- ^ "Populus fremontii". Germplasm Resources Information Network. Agricultural Research Service, United States Department of Agriculture. Retrieved 12 December 2017.
- ^ "Populus fremontii (Fremont's cottonwood)". USDA Plants Profile.
- ^ Schneider, Al. "Populus deltoides". Wildflowers, Ferns, and Trees of Colorado, New Mexico, Arizona, and Utah.
- ^ "Populus". North American Plant Atlas. BONAP. Archived from the original on 2012-04-25.
- ^ Sweep's Library: Firewood Comparison Charts Archived 2006-08-13 at the Wayback Machine The Chimney Sweep.
External links
- Minnesota DNR big tree list. The largest tree by circumference in Minnesota is a Populus deltoides at 394 inches (1,001 centimeters) measured at the trunk 4 and 1/2 feet (137 cm) above the ground. This tree is 106 feet (32.31 meters) tall.
- Monster Ohio Cottowood - 528 points in 2005 on YouTube