Salicaceae
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| A Dwarf Arctic Willow, otherwise known as "Nana," enjoys a bright day |
Salicaceae is a taxonomic family of flowering plants, which is commonly known as the Willow family, but also includes the Cottonwood, Poplar and Aspen. It is the only family of the order Salicales, and contains two Genera. With over 330 species included in Salicaceae, most agree that it is a very diverse family. Every member of the willow family is an angiosperm and deciduous, they can grow from anywhere of a year to over one hundred. The prefer wet soil, but can grow in adverse conditions. Willows have been known to grow in sand dunes or even clay. Their flowers have no petals or sepals, but instead have bracts that support the flower. They often have simple leaves and contain catkins. Members of Salicaceae are trees or shrubs, and exhibit diverse characteristics and habits. They have been used throughout history for medicinal purposes and agriculture. Willows can be found all over the world.
Body Design
With such a diverse family, one may wonder what similar characteristics they all share in common. Each plant species is dioecious, which means they contain "male and female flowers on different plants of the same species." [2] Every member of the Willow family is a flowering plant, other wise known as an angiosperm. [3]
Although the term "Angiosperm" may bring to mind bright and delicate roses or tulip flowers, the Willow family's flowers have no petals or sepals (the green parts that surround and protect the flower bud)[4] Rather than a sepal, Salicaceaes have a tiny, scale-like bracts that serve as a base for the flower. Female flowers contain two to four stigmas, which are the receptive peaks on the pistil (ovule-bearing organ)[5] of a flower, where the pollen is deposited during pollination. Male flowers can have a couple to many stamens (the reproductive organ that produces pollen)[6] on a broad disk-like surface. They also tend to have simple leaves, which, true to it's name, is the most basic shape a leaf can have. The leaf is not divided into any different parts and has no split down the middle. [7] Angiosperms characteristically contain two initial pairs of leaves (cotyledons) produced by the seeds from the species' flower, though sometimes there can be more. [8] Salicaceaes are also deciduous plants, so they shed their leaves in the fall.[9] The Willow family is made up of namely trees and shrubs, all containing stipules, which are pairs of small growths at the base of a leaf stalk or stem that resemble leaves and flowers. [10]
Some of the characteristics that distinguish the many species within the Salicaceae family are: erect or drooping catkins, (which are compact flowers without petals that group together in cylindrically-shaped clusters),[11]the appearance of the leaf venation, whether the pistils are hairy (glabrous) or not, the height of the plant, if the underside of the leaf has a waxy feeling to it (glaucous), whether the pistils are densely populated with flowers or not, and many others. Fauna belonging to this family are very hard to differentiate taxonomically, for many of the species look extremely similar. Sometimes the only difference between two species is whether or not the catkins develop before the leaves do. To make it even more difficult, the names of the species change quite often or are elevated or moved down to the species or subspecies level. This is a challenging family to take on, even for an expert. Despite this, members of the Willow family are quite beautiful and important to the world. [7]
Life Cycle
Because members of the Salicaceae family are deciduous, they grow leaf buds in the spring, have fully grown leaves and flowers by summer, drop their leaves in the fall and become dormant in the winter. This cycle repeats year after year. All plants belonging in the willow family are angiosperms as well. This means that they alternate between a diploid sporophyte generation, and a haploid gametophyte generation. During sexual reproduction, one sperm nucleus fertilizes the egg within the willow's flower to form a zygote, while the other sperm nucleus combines with the two polar nuclei to form the endosperm. An endosperm is the "tissue that surrounds and nourishes the embryo in the angiosperm seed" [12] The this point the seed sprouts in the soil and begins to grow into a willow plant. Reproductive organs will begin to grow in order for the plant to reproduce complete the life cycle. [13] Members of the Salicaceae family can live anywhere from one year to over one hundred.
Ecology
The diverse family of Salicaceae are very important ecologically. They are imperative during succession, a “process of ecological change, involving the progressive replacement of earlier biotic communities with others over time.” This can be in result of an environmental disaster, like a fire, flood, etc. During the recovery period after such an event, members of the Willow family often sprout up. Willows also provide forage for many types of animals, including rabbits, hares, moose, and deer. [14]
Plant species belonging to the Salicaceae family reproduce sexually, with wind being the main contributor for aiding the spread of pollen. Willows are able to grow in many areas of the world, predominantly wetland areas. Salicaceae grow across the United States, Europe, Canada, China, Eurasia, and many other locations. Although many species of Salicaceae enjoy large quantities of water, there are always exceptions. S. purpurea, the purple osier, grows in very dry conditions, and has even been found growing on sand dunes. Willows are viewed as some of the easiest plants to grow and propagate. In many cases, if a farmer sticks a stem from a willow into the ground it can start growing rapidly. Willows are known to be able to thrive in adverse conditions. Biomass growers even grow willow trees from drilled holes in clay.
Willows are very vigorous trees and can grow at a very rapid rate. Many types can grow up to 1.5 inches a day during optimal conditions in the summer months. These fast growing plants, specifically the Goat Willow, S. caprea (known as a common osier), and S. viminalis can grow twenty feet tall in three years and produce sixteen to eighteen tons of burnable timber. Willow shrubs are a valuable renewable resource because of its ability to grow rapidly and be cropped yearly.[15]
Salicaceae in History
Cottonwood plants, belonging to the Salicaceae family, have played a very important part in history all around the world. Fragments of cotton textiles have been discovered in the Indus Valley that are dated around 3000 BC. The economies of many ancient civilizations have depended on the production and use of cotton. Written records (The earliest from South Asia, written around 1500 BC) have placed a heavy importance on the skills of spinning, weaving and dyeing cotton. India, which throughout history has been one of the largest exporters of cotton, is believed to have developed many different textiles and ways to dye cotton as early as 200 BC to 500 AD. India's cotton was most likely exported to Greece before the trade routes between Asia and Europe were established by Alexander the Great. Herodotus, the famous Greek historian, even wrote about the Indian's use of the cottonwood plant. He described them as, "trees that bore wool, surpassing in beauty and in quality the wool of sheep; and the Indians wear clothing from these trees." [16]
Willow weaving, the art of manipulating the growth of the stems and branches of willow trees is very popular among natural artists. This form of art has apparently been popular for thousands of years, for early examples of willow weaving has been discovered at the Somerset lake villages at Glastonbury and Meare in Britain. These villages were thriving agricultural communities 150 B.C. Of course, willow weaving back than had a more productive purpose, like forming the plant's branches into baskets or platters. The main types of willows used for basket weaving are S. triandra, S. viminalis and S. purpurea.
Willows also have been used for early forms of medicine. Aspirin, which has been derived from salicylic acid, comes from the bark of "White Willow", otherwise known as S. alba. Tea made from the leaves of the willow trees has been used to help ease rheumatism and treat nervous insomnia throughout history.[15] Currently, salicylic acid is used in skin products designed for people with sensitive skin. It can be used for both acne and dandruff treatment. It has the ability to stimulate new skin cells and clear away dead ones. Salicylic acid is also used in toothpaste as an antiseptic to get rid of harmful bacteria. The healing qualities of salicylic acid has been used to aid stomach relief. For thousands of years salicylic acid has been used to quell a fever as well.[17]
References
- ↑ 1.0 1.1 [1].USDA. Web. accessed 7,May 2012. Author unknown
- ↑ Author unknown.Dioecious.BING. Web. Accessed 7,May 2012.
- ↑ Author unknown. Angiosperm.BING Web. accessed 7, May 2012.
- ↑ Author unknown. [2].TheFreeDictionary. Web. accessed 9,May 2012.
- ↑ Author unknown. [3].TheFreeDictionary. Web. accessed 9,May 2012.
- ↑ Author unknown. [4].TheFreeDictionary. Web. accessed 9,May 2012.
- ↑ 7.0 7.1 Unknown Author.Salicaceae : Willow Family. CYSIP: Botany. Web. Accessed 9 May 2012.
- ↑ Author unknown. Cotyledons.BING. Web. accessed 7,May 2012.
- ↑ Author unknown [5].encyclopedia.com. Web. accessed 7,May 2012.
- ↑ Author unknown[6].BING. Web. accessed 7,May 2012.
- ↑ Author unknown.[7].TheFreeDictionary. Web. accessed 9,May 2012.
- ↑ Unknown Author. endosperm. britannica. Web. Accessed 21, May 2012.
- ↑ Unknown Author. The life cycle of angiosperm. Scitable. Web. Accessed 21, May 2012.
- ↑ Steve Fuller.Economic And Ecological Importance Of Willows. Willow Family. Web. Accessed 23 May 2012.
- ↑ 15.0 15.1 Steve Fuller.WORKING WITH LIVING WILLOW. Permaculture. Web. Accessed 23 May 2012.
- ↑ Unknown Author. Cotton-History. Plant Cultures. Web. Accessed 9 May 2012.
- ↑ Unknown Author.Salicylic Acid vs Benzoyl Peroxide. Murad. Web. Accessed 23 May 2012.
