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Solidago - Goldenrod

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Category Perennial, Groundcover
Kingdom Plantae
Division Magnoliophyta
Family Compositae
Species in this genus
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Solidago, commonly called goldenrods, is a genus of about 100 species of Flowering plants in the family Asteraceae. Most are herbaceous Perennial species found in the meadows and pastures, along roads, ditches and waste areas in North America. There are also a few species native to Mexico, South America, and Eurasia. Some American species have also been introduced into Europe and other parts of the world.


Solidago species are perennials growing from woody caudices or rhizomes. They have stems that can be decumbent to ascending or erect, ranging in height from 5 to 100 or more centimeters. Some species have stems that branch near the top. Some Solidago species are hairless others have strigose, strigillose, hispid, or short-villous hairs. The basal leaves in some species remain persistent through flowering, while in others the basal leaves are shed before flowering. The leaf margins are often serrate, and leaf faces may be hairless or densely hairy; the distal leaves are sometimes 3-nerved, and hairless or sparsely to densely hairy with scabrous, strigillose, or villous hairs. In some species the upper leaves are stipitate-glandular or sometimes resinous. The flowering heads usually radiate, sometimes discoid, with (1–)2 to 1500+ florets in racemiform (club-shaped or pyramidal), paniculiform or corymbo-paniculiform, or sometimes secund arrays. The involucres are campanulate to cylindric or attenuate. The ray florets are pistillate and fertile. The corollas are yellow or rarely white and are usually hairless. The disc florets are bisexual and fertile and number 2 to 35 typically, but is some species there maybe up to 60 florets. The corollas of the disc florets are yellow and the tubes are shorter than the throats. The fruits are cypselae, which are narrowly obconic to cylindric in shape, they are sometimes somewhat compressed. The cypselae have 8 to 10 ribs usually and are hairless or moderately covered with stiff slender bristles. The pappi are persistent with barbellate bristles.<ref name="fna" />

The many goldenrod species can be difficult to distinguish, due to their similar bright, golden yellow flower heads that bloom in late summer. Goldenrod is often unfairly blamed for causing Hay fever in humans. The pollen causing these allergy problems is mainly produced by Ragweed (Ambrosia sp.), blooming at the same time as the goldenrod, but is wind-pollinated. Goldenrod Pollen is too heavy and sticky to be blown far from the flowers, and is thus mainly pollinated by insects. Frequent handling of goldenrod and other flowers, however, can cause allergic reactions, leading some florists to change occupation.
Solidago species are easily recognized by their golden inflorescence with hundreds of small capitula, some species have their flowers in spike-like inflorescences and others have axillary Racemes. They have slender stems, usually hairless but S. canadensis shows hairs on the upper stem. They can grow to a length between 60 cm and 1.5 m. Their alternate leaves are linear to lanceolate. Their margins are usually finely to sharply serrated.
Propagation is by wind-disseminated Seeds or by spreading underground Rhizomes which can form colonies of vegetative clones of a single plant. They are mostly short-day plants and bloom in late summer and early fall. Some species produce abundant nectar when moisture is plentiful, or when it is warm and sunny.

Use and cultivation

Parts of some goldenrods can be edible when cooked. Goldenrods can be used for decoration and making Tea. Goldenrods are, in some places, held as a sign of good luck or good fortune. They are considered Weeds by many in North America but they are prized as garden plants in Europe, where British gardeners adopted goldenrod long before Americans did as garden subjects. Goldenrod only began to gain some acceptance in American gardening (other than wildflower gardening) during the 1980s.
They have become invasive species in other parts of the world including China; and Solidago canadensis which was introduced as a garden plant in Central Europe, has become common in the wild and in Germany is considered an Invasive species that displaces native vegetation from its natural habitat.

Honey from goldenrods often is dark and strong due to admixtures of other nectars. However when there is a strong Honey flow, a light (often water white), spicy-tasting honey is produced. While the bees are ripening the honey produced from goldenrods it has a rank odor and taste, but finished honey is much milder.
Goldenrod is a Companion plant, playing host to some beneficial insects, and repelling some pests. They are used as a food source by the Larvae of various Lepidoptera species (see List of Lepidoptera that feed on goldenrods). The invading larva induces the plant to form a bulbous tissue mass (called a Gall) around it, upon which the larva then feeds. Various Parasitoid wasps find these galls and lay eggs in the larvae, penetrating the bulb with their Ovipositor. Woodpeckers have adapted to peck open the galls and eat the insect in the center.<ref>D. A. Shealers, J. P. Snyder, V. C. Dreisbach, D. F. Sunderlin, and J. A. Novak (July 1999). "Foraging patterns of Eastern gray squirrels (Sciurus carolinensis) on goldenrod gall insects, a potentially important winter food resource". The American Midland Naturalist 142 (1): 102–109. doi:10.1674/0003-0031(1999)142[0102:FPOEGS]2.0.CO;2.;doi=10.1674%2F0003-0031(1999)142%5B0102%3AFPOEGS%5D2.0.CO%3B2. </ref>

File:Solidago canadensis 20050815 248.jpg
Solidago canadensis 20050815 248.jpg

Cultivated species

Cultivated goldenrods include: S. bicolor, S, caesia, S. canadensis, S. cutleri, S. riddellii, S. rigida, S. shortii, and S. virgaurea. A number of cultivars have been selected and a number of them are of hybrid origin. A putative hybrid with aster, known as x Solidaster is less unruly, with pale yellow flowers, equally suitable for dried arrangements. Molecular and other evidence points to Solidaster (at least Cultivar Lemore) being a hybrid of Solidago ptarmicoides and Solidago canadensis (the former is now placed in Solidago, but is the "aster" of the name, as it has had a checkered taxonomic past).<ref>Schilling, E.E., J.B. Beck, P.J. Calie, and R.L. Small (2008). "Molecular analysis of Solidaster cv. Lemore, a hybrid goldenrod (Asteraceae)". Journal Botanical Research Institute of Texas 2: 7–18.;!--None--&gt; </ref>

Industrial use

Inventor Thomas Edison experimented with goldenrod to produce Rubber, which it contains naturally. Edison created a fertilization and cultivation process to maximize the rubber content in each plant. His experiments produced a plant that yielded as much as 12 percent rubber. The rubber produced through Edison's process was resilient and long lasting. The tires on the Model T given to him by his friend Henry Ford were made from goldenrod. Examples of the rubber can still be found in his laboratory, elastic and rot free after more than 50 years. However, even though Edison turned his research over to the U.S. government a year before his death, goldenrod rubber never went beyond the experimental stage.

Medicinal use

Solidago virgaurea is used in a traditional kidney tonic by practitioners of herbal medicine to counter inflammation and irritation caused of bacterial infections or Kidney stones.Goldenrod has also been used as part of a tincture to aid in cleansing of the kidney/bladder during a healing fast, in conjunction with potassium broth and specific juices. Solidago odora is sold as a medicinal, for these issues: mucus, kidney/bladder cleansing and stones, colds, digestion, and a tea is made from the leaves and flowers for sore throat, snake bite, fever, kidney and bladder problems, cramps, colic, colds, diarrhea, measles, cough and asthma. A poultice is used for boils, burns, headache, toothache, wounds, and sores. Native Americans chewed the leaves to relieve sore throats and chewed the roots to relieve toothaches.<ref name="Silverthorne2002">Elizabeth Silverthorne (2002). Legends and Lore of Texas Wildflowers. Texas A&amp;M University Press. pp. 61–. ISBN 9781585442300.;pg=PA61. Retrieved 4 October 2010. </ref>



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