Family Salicaceae – Willow, Poplar and Aspen

Family Salicaceae – Willow, Cottonwood, Aspen
There are only two genera in this family, Salix (willows), and Populus (poplars). Trees in this family have a
strong affinity for water and harbor nymphs and
other fanciful arboreal deities.

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swamp cottonwood leaflet
Archetypal leaflet for Populus genus; Swamp Cottonwood Populus heterophylla
There are only two genera in this family, Salix (willows), with about 300 species, and Populus (poplars), with barely 40 species. Salicaceae are found throughout the temperate parts of the world, with the majority of species occurring in the north; both willows and poplars have a strong affinity for water, and are commonly found near ponds and along watercourses.

The genus Populus accounts for not only the heaviest, but also the oldest organism extant: Pando (Latin for "I spread"), aka "the trembling giant," is a clone colony of  male quaking aspen, (Populus tremuloides) a single living organism identified by identical genetic markers.  Assumed to have one massive underground root system, the plant is estimated to weigh 6,000,000 kg (13,227,735 pounds) making it the heaviest known organism of any kind. Estimated at 80,000 years old, Pando is also the oldest living organism on Earth. Pando is located in the Fishlake National Forest in Utah [6].

Willow bark was steeped as tea by native Americans, and the young twigs and bark chewed to relieve headaches. It was later found the active ingredient was salicylic acid, the basis of today’s aspirin. The chemical name for aspirin comes from the willow family name.

All reproductive events (pollination, fertilization, and seed dispersal) are wind-mediated within almost all species this family.  Cottonwoods, especially, are noted for their profusion of white tufted seeds, which can be produced in such numbers they accumulate in "snowdrifts."

The Willow family of trees (Salicaceae) has 350 or so species of willows and poplars, which are mainly natives of the Northern Hemisphere. The one uniting feature of all Salicaceae is their flowers; they have neither petals nor sepals but are borne in catkins that usually appear with or before the tree's new leaves. Both willows and poplars prefer moist sites and hybridize so easily identification is sometimes difficult.

Golden Weeping Willow
Golden Weeping Willow – Salix alba 'Tristis'

Golden weeping willow is a fast-growing, massive tree reaching up to 80 feet in height. Although main branches grow upward, the secondary ones grow straight down, creating the graceful weeping effect for which it is renowned. The trunk is brown with a distinctly corky bark. The pendant stems are yellow green. The narrow, deciduous leaves are pointed and green to yellow-green above, pale below. They turn yellow in the fall.

Often found growing wild along streams and watercourses, the golden weeping willow has characteristics that might have one regretting a decision to use them in home landscapes. Although willows in general grow easily in most moist soils, they require watering during periods of drought, lest they lose their leaves in copious quantities. The brittle wood is subject to windthrow and breakage, and the tree sheds its woody parts regularly, creating a never-ending litter problem.

These huge cottonwoods at The Morton Arboretum are about 120 feet tall, age unknown. One supposes they were here when Joy Morton began his museum of woody plants back in the early 1920s.

As children, we loved the cottonwoods 'round our vicinity in northern Illinois. They were easy to climb and easy to nail things to; they became our favorite haunt when we learned to build tree houses out of "leftover" lumber we so expertly snagged from home construction sites. Who said children were ethical? We certainly weren't. Some of us did end up in jail, alas, in later years!

In any event, it's a wonder none of us were killed or at least seriously injured; we were working at 50 feet or more, and sometimes wielding pea-shooters at neighborhood toughs trying to oust us from our aerie. You can put somebody's eye out with those things!

White poplar Poplars have wind-pollinated catkins and leaves whose broad blades have long petioles which may be flattened at one end. Their shoots bear terminal buds, and all their buds have overlapping scales. Hybrids grow more vigorously and provide better timber than their parents. Dark green, glossy poplar leaves toss in the slightest breeze, revealing silvery-white undersides.

White Poplars (left) are native to Europe, Asia, and North Africa; they were introduced to North America during colonial times. They grow rapidly and spread readily by root sprouts – so readily they often become undesirable as weeds. Along with Quaking Aspen, white poplar belongs to a group of poplars with smooth barks and coarsely serrate leaves.

If you're ever lucky enough to se a few of these trees from a distance on a windy, sunny day, you'll  not soon forget the sight. It's difficult to describe the almost eerie pale graan-blue of the leaflet undersides shimmering in the breeze.

I have vivid graphic memories of just such groves of trees from my ealy childhood; yet what goes along with is a good sense of the absence of information, of not knowing what it was I was looking at – but still knowing it was special somehow.

The white poplars at left were photographed at The Morton Arboretum, on the west side near the river. They are every bit of 80 feet tall and have 2-foot diameter trunks.

Black Willow foliage
Commonly called Gooding willow, Dudley willow, swamp willow, and sauz, black willow is the largest and the only commercially important willow of about 90 species native to North America. It is more distinctly a tree throughout its range than any other native willow; 27 species attain tree size in only part of their range. Other names sometimes used are swamp willow, Goodding willow, southwestern black willow, Dudley willow, and sauz (Spanish). This short-lived, fast-growing tree reaches its maximum size and development in the lower Mississippi River Valley and bottom lands of the Gulf Coastal Plain. Stringent requirements of seed germination and seedling establishment limit black willow to wet soils near water courses, especially floodplains, where it often grows in pure stands. Black willow is used for a variety of wooden products and the tree, with its dense root system, is excellent for stabilizing eroding lands.
Black Willow
Black Willow
Salix nigra
Eastern Cottonwood Tree
Eastern Cottonwood Tree
Populus deltoides
Image: White Poplar
White Poplar Tree
Populus alba
Golden Weeping Willow - Salix alba 'Tristis'
Golden Weeping Willow
Salix alba
Populus heterophylla
Populus heterophylla
Swamp Cottonwood

Crack Willow
Salix fragilis
Balsam Poplar
Populus balsamifera
Balsam Poplar
Balsam Poplar – Populus balsamifera 05/14/2015
Black Willow – Salix nigra 05/14/2015
Crack Willow – Salix fragilis 05/14/2015
Eastern Cottonwood – Populus deltoides 05/14/2015
Flowering Plants Index 05/14/2015
Golden Weeping Willow – Salix alba 'Tristis' 05/14/2015
Swamp Cottonwood – Populus heterophylla 05/14/2015
Tree Encyclopedia 05/14/2015
Tree Encyclopedia for Mobile 02/10/2015
Tree Encyclopedia Index 05/14/2015
Tree Index for Mobile 05/14/2015
White Poplar – Populus alba 05/14/2015
White Willow – Salix alba 05/14/2015
Yellow Cheerfulness Narcissus 05/14/2015
1. USDA NRCS Plant Materials Program," EASTERN COTTONWOOD"
2. NATIONAL AUDUBON SOCIETY, National Audubon Society Field Guide to North American Trees
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