Cassia
Cassia (Cinnamomum aromaticum, synonym C. cassia) is an evergreen tree native to southern China, Bangladesh, India, and Vietnam. Like its close relative, cinnamon (Cinnamomum zeylanicum, also known as "true cinnamon" or "Ceylon cinnamon"), it is used primarily for its aromatic bark, which is used as a spice, often under the culinary name of "cinnamon". The buds are also used as a spice, especially in India and in Ancient Rome.
The Cassia tree grows to 10-15 m tall, with greyish bark and hard elongated leaves that are 10-15 cm long and have a decidedly reddish colour when young.

# Production and uses
Cassia is a close relative to the cinnamon (Cinnamomum verum, Cinnamomum zeylanicum, or "true cinnamon"), Saigon cinnamon (Cinnamomum loureiroi, also known as "Vietnamese cinnamon"), Camphor laurel (Cinnamomum camphora), Malabathrum (Cinnamomum tamala) and Cinnamomum burmannii (also know as "Indonesian cinnamon") trees. As with these species, the dried bark of cassia is used as a spice. Cassia's flavour, however, is less delicate than that of true cinnamon; for this reason, the less expensive cassia is sometimes called "bastard cinnamon".
Whole branches and small trees are harvested for cassia bark, unlike the small shoots used in the production of cinnamon; this gives cassia bark a much thicker and rougher texture than that of true cinnamon.
Most of the spice sold as cinnamon in the United States and Canada (where true cinnamon is still generally unknown) is actually cassia.  In some cases, cassia is labeled "Chinese cinnamon" to distinguish it from the more expensive true cinnamon (Cinnamomum zeylanicum), which is the preferred form of the spice used in Mexico and Europe .
"Indonesian cinnamon" can also refer to Cinnamomum burmannii, which is also 
commonly sold in the United States, labeled only as cinnamon.
Cassia (Cinnamomum aromaticum) is produced in both China and Vietnam.  Until the 1960s, Vietnam was the world's most important producer of Saigon cinnamon, a species which has a higher oil content than Cinnamomum aromaticum, and consequently has a stronger flavor. Saigon cinnamon is so closely related to cassia that it was often marketed as cassia (or, in North America, "cinnamon"). Of the three forms of cassia, it is the form which commands the highest price. Because of the disruption caused by the Vietnam War, however, production of another form of cassia, Cinnamomum burmannii, in the highlands of the Indonesia on island of Sumatra was increased to meet demand, and Indonesia remains one of the main exporters of cassia today. Indonesia cassia has the lowest oil content of the three types of cassia and, consequently, commands the lowest price. Saigon cinnamon, only having become available again in the United States since the early 21st century, has an intense flavour and aroma and a higher percentage of essential oils than Indonesian cassia. Cinnamomum aromaticum has a stronger and sweeter flavor, similar to Saigon cinnamon, although the oil content is lower. In China, cassia is known as Tung Hing. 
Cassia bark (both powdered and in whole, or "stick" form) is used as a flavouring agent for candies, desserts, baked goods, and meat; it is specified in many curry recipes, where cinnamon is less suitable. Cassia is sometimes added to true cinnamon but is a much thicker, coarser product. Cassia is sold as pieces of bark (as pictured below) or as neat quills or sticks. Cassia sticks can be distinguished from true cinnamon sticks in the following manner: Cinnamon sticks have many thin layers and can easily be made into powder using a coffee or spice grinder, whereas cassia sticks are extremely hard, are usually made up of one thick layer, and can break an electric spice or coffee grinder if one attempts to grind them without first breaking them into very small pieces.
Cassia buds, although rare, are also occasionally used as a spice. They resemble cloves in appearance and flavor.photo

## Health benefits and risks
Cassia (called rou gui;  in Chinese) is used in traditional Chinese medicine, where it is considered one of the 50 fundamental herbs.
A 2003 study published in the DiabetesCare journal followed Type 2 diabetics ingesting 1, 3, or 6 grams of cassia daily. Those taking 6 grams showed changes after 20 days, and those taking lesser doses showed changes after 40 days. Regardless of the amount of cassia taken, they reduced their mean fasting serum glucose levels 1829%, their triglyceride levels 2330%, their LDL cholesterol 727%, and their total cholesterol 1226%, compared to others taking placebos.
The effects, which may even be produced by brewing a tea from cassia bark, may also be beneficial for non-diabetics to prevent and control elevated glucose, insulin, and blood lipid levels. However, chemist Richard Anderson says that his research has shown that most, if not all, of cinnamon's antidiabetic effect is in its water-soluble fraction, not the oil (the ground cinnamon spice itself should be ingested for benefit, not the oil or a water extraction). In fact, some cinnamon oil-entrained compounds could prove toxic in high concentrations.   Cassia's effects on enhancing insulin sensitivity appear to be mediated by polyphenols .  Despite these findings, cassia should not be used in place of anti-diabetic drugs, unless blood glucose levels are closely monitored, and its use is combined with a strictly controlled diet and exercise program.
Researchers at the University of California, Santa Barbara have discovered an extract of common cinnamon that contains a class of small organic molecules that inhibit several key processes in Alzheimers disease. The cinnamon extract inhibits the aggregation of tau and disassembles fibers that have already formed, suggesting that neurofibrillary tangles can possibly be reversed by these compounds. The extract exhibits potent inhibitory activity, is orally available, water-soluble, non-toxic, and the bioactive molecules are likely brain permeable. The extract is readily produced in large quantities and can be encapsulated in powder form for oral 
administration. These properties make the cinnamon extract a highly favourable substance for development into an effective therapeutic to slow or prevent Alzheimers disease.
There is also much anecdotal evidence that consumption of cassia has a strong effect in lowering blood pressure, making it potentially useful to those suffering from hypertension. The USDA has three ongoing studies that are monitoring the blood pressure effect.
Though the spice has been used for thousands of years, there is concern that there is as yet no knowledge about the potential for toxic buildup of the fat-soluble components in cassia, as anything fat-soluble could potentially be subject to toxic buildup. There are no concluded long-term clinical studies on the use of cassia for health reasons.
Due to a toxic component called coumarin, European health agencies have warned against consuming high amounts of cassia.

# History
In classical times, four types of cinnamon were distinguished (and often confused):
- Cassia (Hebrew qsi`a), the bark of Cinnamomum iners from Arabia and Ethiopia
- Cinnamon proper (Hebrew qinnamon), the bark of Cinnamomum zeylanicum from Sri Lanka
- Malabathrum or Malobathrum (from Sanskrit ,  tamalapattram, literally "dark-tree leaves"), Cinnamomum malabathrum from the North of India
- Serichatum, Cinnamomum aromaticum from Seres, that is, China.
In Exodus 30:23-4, Moses is ordered to use both sweet cinnamon (Kinnamon) and cassia (qsi`a) together with myrrh and cannabis 
 or sweet calamus (qne-bosem, literally cane of fragrance) and olive oil to produce a holy oil to anoint the Ark of the Covenant. Psalm 45, 8, mentions the garments of Torah scholars that smell of myrrh, aloes and cassia.
An early reference to the trade of cinnamon occurs around 100 BC in Chinese literature. After the explorer Zhang Qian's return to China, the Han Dynasty pushed the Xiongnu back and trade and cultural exchange flourished along the Northern Silk Road. Goods moving by caravan to the west included gold, rubies, jade, textiles, coral, ivory and art works. In the opposite direction moved bronze weapons, furs, ceramics and cinnamon bark. The first Greek reference to kasia is found in a poem by Sappho in the 7th century B.C.
According to Herodotus, both cinnamon and cassia grow in Arabia, together with incense, myrrh, and ladanum, and are guarded by winged serpents. The phoenix builds its nest from cinnamon and cassia. But Herodotus mentions other writers that see the home of Dionysos, e.g., India, as the source of cassia. While Theophrastus gives a rather good account of the plants, a curious method for harvesting (worms eat away the wood and leave the bark behind), Dioscorides seems to confuse the plant with some kind of water-lily.
Pliny (nat. 12, 86-87) gives a fascinating account of the early spice trade across the Red Sea in "rafts without sails or oars", obviously using the trade winds, that costs Rome 100 million sesterces each year. According to Pliny, a pound (the Roman pound, 327 g) of cassia, cinnamon, or serichatum cost up to 300 denars, the wage of ten months' labour. Diocletian's Edict on Maximum Prices from 301 AD gives a price of 125 denars for a pound of cassia, while an agricultural labourer earned 25 denars per day.
The Greeks used kasia or malabathron to flavour wine, together with absinth (Artemisia absinthia). Pliny mentions cassia as a flavouring agent for wine as well  Malabathrum leaves (folia) were used in cooking and for distilling an oil used in a caraway-sauce for oysters by the Roman gourmet Gaius Gavius Apicius.  Malabathrum is among the spices that, according to Apicius, any good kitchen should contain.
Egyptian recipes for kyphi, an aromatic used for burning, included cinnamon and cassia from Hellenistic times onwards. The gifts of Hellenistic rulers to temples sometimes included cassia and cinnamon as well as incense, myrrh, and Indian incense (kostos), so we can conclude that the Greeks used it in this way too.
The famous Commagenum, an unguent produced in Commagene in present-day eastern Turkey, was made from goose-fat and aromatised with cinnamon oil and spikenard (Nardostachys jatamansi). Malobrathum from Egypt (Dioscorides I, 63) was based on cattle-fat and contained cinnamon as well; one pound cost 300 denars. The Roman poet Martial (VI, 55) makes fun of Romans who drip unguents, smell of cassia and cinnamon taken from a bird's nest, and look down on him who does not smell at all.
Cinnamon, as a warm and dry substance, was believed by doctors in ancient times to cure snakebites, freckles, the common cold, and kidney troubles, among other ailments.