Taxus cuspidata

Taxus Cuspidata is the Japanese Yiw (or spreading Yiw) and is a member the genus taxus. It’s native to Japan, Korea and the extreme southeast corner of Russia.

It is an evergreen tree or large shrub growing to 10-18 m tall, with a trunk up to 60 cm diameter. The leaves are lanceolate, flat, dark green, 1-3 cm long and 2-3 mm broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flattish rows either side of the stem except on erect leading shoots where the spiral arrangement is more obvious.

Each seed cone contains a single seed, 4-8 mm in length, partially surrounded by a modified scaling, which eventually develops into an aril (8-12 mm in length, wide at the ends, and 8-12 mm in width). After pollination, the arils mature in 6-9 months. Individual trees from Sikhote-Alin are known to have been 1,000 years old.

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Taxine alkaloids are a group that causes toxic reactions in the entire yew bush. Their cardiotoxicity is well known and act via calcium and sodium channel antagonism, causing an increase in cytoplasmic calcium currents of the myocardial cells. The seeds contains the highest concentrations of these alkaloids. If any leaves or seeds of the plant are ingested, urgent medical advice is recommended as well as observation for at least 6 hours after the point of ingestion. The most cardiotoxic taxine is Taxine B followed by Taxine A; Taxine B also happens to be the most common alkaloid in the Taxus species. Yew poisonings are relatively common in both domestic and wild animals who consume the plant accidentally. The taxine alkaloids are absorbed quickly from the intestine and in high enough quantities can cause death due to general cardiac failure, cardiac arrest or respiratory failure. Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves. Taxus Baccata leaves contain approximately 5 mg of taxines per 1g of leaves. The estimated (i.e. not by any means a fact) lethal dose (LD_min) of Taxus baccata leaves is 3.0-6.5 mg/kg body weight for humans There is currently no known antidotes for yew poisoning, but drugs such as atropine have been used to treat the symptoms. Taxine is present in the plant throughout the year. The highest concentrations are seen during winter. Dried yew plant material retains its toxicity for several months and even increases its toxicity as the water is removed, fallen leaves are also toxic. Although poisoning usually occurs when leaves of yew trees are eaten, in at least one case a victim inhaled sawdust from a yew tree.

The book that follows made clear that it was very difficult to measure the taxine alkaloids. This is why there are so many different results.
Tests of the minimum lethal dose, oral _min and for many other animals were done:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horse 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

See Taxine alkaloids for symptoms of toxic human reactions

The genus’ male and monoecious species of yews release toxic pollen. This can lead to mild symptoms. See Taxine alkaloids. Asthma can also be triggered by pollen. These pollen grains measure only 15 microns and pass easily through most windows.

Taxus cuspidata, the Japanese yew or spreading yew, is a member of the genus Taxus, native to Japan, Korea, northeast China and the extreme southeast of Russia.

The evergreen shrub or tree can grow to 10-18m high and have a trunk of up to 60cm. The lanceolate leaves are flat, dark green, and 1-3 cm in length. They can be arranged spirally on the stem with the base twisted to align them in two flattish rows on either side. This is except for the erect leading shoots, where the spiral arrangement is more apparent.

Each seed cone contains a single seed, 4-8 mm in length, partially surrounded by a modified scaling, which eventually develops into an aril (8-12 mm in length, wide at the ends, and 8-12 mm in width). The arils are mature 6-9 months after pollination. Sikhote-Alin trees are estimated to be over 1,000 years old.

Uses

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity

The entire yew bush, except the aril (the red flesh of the berry covering the seed), is toxic due to a group of chemicals called taxine alkaloids. Their cardiotoxicity is well known and act via calcium and sodium channel antagonism, causing an increase in cytoplasmic calcium currents of the myocardial cells. The seeds contains the highest concentrations of these alkaloids. If any leaves or seeds of the plant are ingested, urgent medical advice is recommended as well as observation for at least 6 hours after the point of ingestion. The most cardiotoxic taxine is Taxine B followed by Taxine A; Taxine B also happens to be the most common alkaloid in the Taxus species. Yew poisonings are relatively common in both domestic and wild animals who consume the plant accidentally. The taxine alkaloids are absorbed quickly from the intestine and in high enough quantities can cause death due to general cardiac failure, cardiac arrest or respiratory failure. Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves. Taxus Baccata leaves contain approximately 5 mg of taxines per 1g of leaves. The estimated (i.e. The estimated (i.e. Taxine remains in the plant all year, with maximal concentrations appearing during the winter. Dried yew plant material retains its toxicity for several months and even increases its toxicity as the water is removed, fallen leaves are also toxic. Although poisoning usually occurs when leaves of yew trees are eaten, in at least one case a victim inhaled sawdust from a yew tree.

The book that follows made clear that it was very difficult to measure the taxine alkaloids. This is why there are so many different studies.
Tests of the minimum lethal dose, oral _min and for many other animals were done:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horse 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

See Taxine alkaloids for symptoms of toxic human reactions

Male and monoecious yews in this genus release toxic pollen, which can cause the mild symptoms see Taxine alkaloids. The pollen are also a trigger for asthma. These pollen grains are only 15 microns in size, and can easily pass through most window screens.

References

Taxus Cuspidata is the Japanese Yiw (or spreading Yiw) and is a member the genus taxus. It’s native to Japan, Korea, and the extreme southeast corner of Russia.

The evergreen shrub or tree can grow to 10-18m high and have a trunk of up to 60cm. The lanceolate leaves are flat, dark green, and 1-3 cm in length. They can be arranged spirally on the stem with the base twisted to align them in two flattish rows on either side. This is except for the erect leading shoots, where the spiral arrangement is more apparent.

The seed cones are highly modified, each cone containing a single seed 4-8 mm long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, 8-12 mm long and wide and open at the end. The arils are mature 6-9 months after pollination. Individual trees from Sikhote-Alin are known to have been 1,000 years old.

Uses

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity

The entire yew bush, except the aril (the red flesh of the berry covering the seed), is toxic due to a group of chemicals called taxine alkaloids. They cause an increase in the cytoplasmic calcium currents within myocardial cells and are well-known for their cardiotoxicity. These alkaloids are most concentrated in the seeds. It is important to seek immediate medical attention if any of the leaves or seeds are eaten. Also, it is important to keep the patient awake for at least six hours following ingestion. Taxine B is the most dangerous taxine and Taxine A is the next. Taxine B happens to be the most commonly found alkaloid in Taxus species. Yew poisonings are relatively common in both domestic and wild animals who consume the plant accidentally. The taxine alkaloids are absorbed quickly from the intestine and in high enough quantities can cause death due to general cardiac failure, cardiac arrest or respiratory failure. Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves. Taxus Baccata leaves have approximately 5 mg taxines per 1g. The estimated (i.e. not by any means a fact) lethal dose (LD_min) of Taxus baccata leaves is 3.0-6.5 mg/kg body weight for humans There is currently no known antidotes for yew poisoning, but drugs such as atropine have been used to treat the symptoms. Taxine remains in the plant all year, with maximal concentrations appearing during the winter. Dried yew plant material retains its toxicity for several months and even increases its toxicity as the water is removed, fallen leaves are also toxic. Although poisoning usually occurs when leaves of yew trees are eaten, in at least one case a victim inhaled sawdust from a yew tree.

The book that follows made clear that it was very difficult to measure the taxine alkaloids. This is why there are so many different results.
Minimum lethal dose, oral LD_min for many different animals were tested:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horses 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

For symptoms of human toxicity see Taxine alkaloids

Male and monoecious yews in this genus release toxic pollen, which can cause the mild symptoms see Taxine alkaloids. The pollen are also a trigger for asthma. These pollen grains are only 15 microns in size, and can easily pass through most window screens.

References

Taxus cuspidata, the Japanese yew or spreading yew, is a member of the genus Taxus, native to Japan, Korea, northeast China and the extreme southeast of Russia.

The evergreen shrub or tree can grow to 10-18m high and have a trunk of up to 60cm. The leaves are lanceolate, flat, dark green, 1-3 cm long and 2-3 mm broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flattish rows either side of the stem except on erect leading shoots where the spiral arrangement is more obvious.

The seed cones are highly modified, each cone containing a single seed 4-8 mm long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, 8-12 mm long and wide and open at the end. The arils are mature 6-9 months after pollination. Individual trees from Sikhote-Alin are known to have been 1,000 years old.

Uses

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity

The entire yew bush, except the aril (the red flesh of the berry covering the seed), is toxic due to a group of chemicals called taxine alkaloids. They cause an increase in the cytoplasmic calcium currents within myocardial cells and are well-known for their cardiotoxicity. These alkaloids are most concentrated in the seeds. It is important to seek immediate medical attention if any of the leaves or seeds are eaten. Also, it is important to keep the patient awake for at least six hours following ingestion. Taxine B is the most dangerous taxine and Taxine A is the next. Taxine B is also the most commonly found alkaloid in Taxus species. Yew poisonings can be fatal in wild and domestic animals that accidentally eat the plant. Taxine alkaloids are quickly absorbed from the intestine. In large enough amounts, they can cause cardiac failure, respiratory failure, or cardiac arrest. Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves. Taxus Baccata leaves contain approximately 5 mg of taxines per 1g of leaves. The estimated (i.e. not by any means a fact) lethal dose (LD_min) of Taxus baccata leaves is 3.0-6.5 mg/kg body weight for humans There is currently no known antidotes for yew poisoning, but drugs such as atropine have been used to treat the symptoms. Taxine is present in the plant throughout the year. The highest concentrations are seen during winter. Dried yew plant material retains its toxicity for several months and even increases its toxicity as the water is removed, fallen leaves are also toxic. While poisoning is most commonly caused by yew tree leaves being eaten, at least one victim was able to inhale sawdust from a Yew tree.

The following book made it clear that it is very difficult to measure taxine alkaloids and that this is a major reason as to why different studies show different results.
Minimum lethal dose, oral LD_min for many different animals were tested:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horse 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

For symptoms of human toxicity see Taxine alkaloids

Male and monoecious yews in this genus release toxic pollen, which can cause the mild symptoms see Taxine alkaloids. Asthma can also be triggered by pollen. These pollen grains measure only 15 microns and pass easily through most windows.

References

Taxus cuspidata, the Japanese yew or spreading yew, is a member of the genus Taxus, native to Japan, Korea, northeast China and the extreme southeast of Russia.

It is an evergreen tree or large shrub growing to 10-18 m tall, with a trunk up to 60 cm diameter. The lanceolate leaves are flat, dark green, and 1-3 cm in length. They can be arranged spirally on the stem with the base twisted to align them in two flattish rows on either side. This is except for the erect leading shoots, where the spiral arrangement is more apparent.

Each seed cone contains a single seed, 4-8 mm in length, partially surrounded by a modified scaling, which eventually develops into an aril (8-12 mm in length, wide at the ends, and 8-12 mm in width). After pollination, the arils mature in 6-9 months. Individual trees from Sikhote-Alin are known to have been 1,000 years old.

Uses

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity

The entire yew bush, except the aril (the red flesh of the berry covering the seed), is toxic due to a group of chemicals called taxine alkaloids. Their cardiotoxicity is well known and act via calcium and sodium channel antagonism, causing an increase in cytoplasmic calcium currents of the myocardial cells. These alkaloids are most concentrated in the seeds. It is important to seek immediate medical attention if any of the leaves or seeds are eaten. Also, it is important to keep the patient awake for at least six hours following ingestion. Taxine B is the most dangerous taxine and Taxine A is the next. Taxine B is also the most commonly found alkaloid in Taxus species. Yew poisoning is quite common in wild and domestic animals that accidentally eat the plant. The taxine alkaloids are absorbed quickly from the intestine and in high enough quantities can cause death due to general cardiac failure, cardiac arrest or respiratory failure. Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves. Taxus Baccata leaves have approximately 5 mg taxines per 1g. The estimated (i.e. The estimated (i.e. Taxine remains in the plant all year, with maximal concentrations appearing during the winter. The toxicity of dried yew plant material can be retained for many months, and it may even increase as the water is removed. Fallen leaves are also toxic. Although poisoning usually occurs when leaves of yew trees are eaten, in at least one case a victim inhaled sawdust from a yew tree.

The following book made it clear that it is very difficult to measure taxine alkaloids and that this is a major reason as to why different studies show different results.
Tests of the minimum lethal dose, oral _min and for many other animals were done:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horse 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

See Taxine alkaloids for symptoms of toxic human reactions

Male and monoecious yews in this genus release toxic pollen, which can cause the mild symptoms see Taxine alkaloids. Asthma can also be triggered by pollen. These pollen grains measure only 15 microns and pass easily through most windows.

References

Taxus Cuspidata is the Japanese Yiw (or spreading Yiw) and is a member the genus taxus. It’s native to Japan, Korea, and the extreme southeast corner of Russia.

It is an evergreen tree or large shrub growing to 10-18 m tall, with a trunk up to 60 cm diameter. The leaves are lanceolate, flat, dark green, 1-3 cm long and 2-3 mm broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flattish rows either side of the stem except on erect leading shoots where the spiral arrangement is more obvious.

Each seed cone contains a single seed, 4-8 mm in length, partially surrounded by a modified scaling, which eventually develops into an aril (8-12 mm in length, wide at the ends, and 8-12 mm in width). The arils are mature 6-9 months after pollination. Sikhote-Alin trees are estimated to be over 1,000 years old.

Uses

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity

The entire yew bush, except the aril (the red flesh of the berry covering the seed), is toxic due to a group of chemicals called taxine alkaloids. They cause an increase in the cytoplasmic calcium currents within myocardial cells and are well-known for their cardiotoxicity. The seeds contains the highest concentrations of these alkaloids. It is important to seek immediate medical attention if any of the leaves or seeds are eaten. Also, it is important to keep the patient awake for at least six hours following ingestion. The most cardiotoxic taxine is Taxine B followed by Taxine A; Taxine B also happens to be the most common alkaloid in the Taxus species. Yew poisonings are relatively common in both domestic and wild animals who consume the plant accidentally. The taxine alkaloids are absorbed quickly from the intestine and in high enough quantities can cause death due to general cardiac failure, cardiac arrest or respiratory failure. Taxines can also be absorbed easily through the skin. Taxus species should therefore be treated with care, and preferably with gloves. Taxus Baccata leaves contain approximately 5 mg of taxines per 1g of leaves. The estimated (i.e. not by any means a fact) lethal dose (LD_min) of Taxus baccata leaves is 3.0-6.5 mg/kg body weight for humans There is currently no known antidotes for yew poisoning, but drugs such as atropine have been used to treat the symptoms. Taxine is found in the plant throughout the year. The highest concentrations are seen during winter. The toxicity of dried yew plant material can be retained for many months, and it may even increase as the water is removed. Fallen leaves are also toxic. While poisoning is most often caused by the consumption of leaves from yew trees, at least one victim was able to inhale sawdust from a tree.

The following book made it clear that it is very difficult to measure taxine alkaloids and that this is a major reason as to why different studies show different results.
Minimum lethal dose, oral LD_min for many different animals were tested:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horse 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

For symptoms of human toxicity see Taxine alkaloids

Male and monoecious yews in this genus release toxic pollen, which can cause the mild symptoms see Taxine alkaloids. Asthma can also be triggered by pollen. These pollen grains measure only 15 microns and pass easily through most windows.

References

Taxus Cuspidata is the Japanese Yiw (or spreading Yiw) and is a member the genus taxus. It’s native to Japan, Korea, and the extreme southeast corner of Russia.

It is an evergreen tree or large shrub growing to 10-18 m tall, with a trunk up to 60 cm diameter. The lanceolate leaves are flat, dark green, and 1-3 cm in length. They can be arranged in a spiral on the stem with the base twisted to align them in two flattish rows on either side. This is except for the erect leading shoots, where the spiral arrangement is more apparent.

The seed cones are highly modified, each cone containing a single seed 4-8 mm long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, 8-12 mm long and wide and open at the end. The arils are mature 6-9 months after pollination. Sikhote-Alin trees are estimated to be over 1,000 years old.

Uses

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity

The entire yew bush, except the aril (the red flesh of the berry covering the seed), is toxic due to a group of chemicals called taxine alkaloids. Their cardiotoxicity is well known and act via calcium and sodium channel antagonism, causing an increase in cytoplasmic calcium currents of the myocardial cells. The seeds contains the highest concentrations of these alkaloids. It is important to seek immediate medical attention if any of the leaves or seeds are eaten. Also, it is important to keep the patient awake for at least six hours following ingestion. Taxine B is the most dangerous taxine and Taxine A is the next. Taxine B is also the most commonly found alkaloid in Taxus species. Yew poisonings can be fatal in wild and domestic animals that accidentally eat the plant. The taxine alkaloids are absorbed quickly from the intestine and in high enough quantities can cause death due to general cardiac failure, cardiac arrest or respiratory failure. Taxines can also be absorbed easily through the skin. Taxus species should therefore be treated with care, and preferably with gloves. Taxus Baccata leaves have approximately 5 mg taxines per 1g. The estimated (i.e. The estimated (i.e. Taxine remains in the plant all year, with maximal concentrations appearing during the winter. The toxicity of dried yew plant material can be retained for many months, and it may even increase as the water is removed. Fallen leaves are also toxic. Although poisoning usually occurs when leaves of yew trees are eaten, in at least one case a victim inhaled sawdust from a yew tree.

The following book made it clear that it is very difficult to measure taxine alkaloids and that this is a major reason as to why different studies show different results.
Tests of the minimum lethal dose, oral _min and for many other animals were done:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horses 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

For symptoms of human toxicity see Taxine alkaloids

Male and monoecious yews in this genus release toxic pollen, which can cause the mild symptoms see Taxine alkaloids. The pollen are also a trigger for asthma. These pollen grains are only 15 microns in size, and can easily pass through most window screens.

References

Taxus cuspidata, the Japanese yew or spreading yew, is a member of the genus Taxus, native to Japan, Korea, northeast China and the extreme southeast of Russia.

It is an evergreen tree or large shrub growing to 10-18 m tall, with a trunk up to 60 cm diameter. The leaves are lanceolate, flat, dark green, 1-3 cm long and 2-3 mm broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flattish rows either side of the stem except on erect leading shoots where the spiral arrangement is more obvious.

The seed cones are highly modified, each cone containing a single seed 4-8 mm long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, 8-12 mm long and wide and open at the end. After pollination, the arils mature in 6-9 months. Individual trees from Sikhote-Alin are known to have been 1,000 years old.

Uses

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity

The entire yew bush, except the aril (the red flesh of the berry covering the seed), is toxic due to a group of chemicals called taxine alkaloids. Their cardiotoxicity is well known and act via calcium and sodium channel antagonism, causing an increase in cytoplasmic calcium currents of the myocardial cells. The seeds contains the highest concentrations of these alkaloids. It is important to seek immediate medical attention if any of the leaves or seeds are eaten. Also, it is important to keep the patient awake for at least six hours following ingestion. Taxine B is the most dangerous taxine and Taxine A is the next. Taxine B is also the most commonly found alkaloid in Taxus species. Yew poisonings are relatively common in both domestic and wild animals who consume the plant accidentally. Taxine alkaloids are quickly absorbed from the intestine. In large enough amounts, they can cause cardiac arrest, general cardiac failure, or respiratory failure. Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves. Taxus Baccata leaves contain approximately 5 mg of taxines per 1g of leaves. The estimated (i.e. The estimated (i.e. Taxine remains in the plant all year, with maximal concentrations appearing during the winter. The toxicity of dried yew plant material can be retained for many months, and it may even increase as the water is removed. Fallen leaves can also be toxic. Although poisoning usually occurs when leaves of yew trees are eaten, in at least one case a victim inhaled sawdust from a yew tree.

The following book made it clear that it is very difficult to measure taxine alkaloids and that this is a major reason as to why different studies show different results.
Tests of the minimum lethal dose, oral _min and for many other animals were done:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horse 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

See Taxine alkaloids for symptoms of toxic human reactions

The genus’ male and monoecious species of yews release toxic pollen. This can lead to mild symptoms. See Taxine alkaloids. The pollen are also a trigger for asthma. These pollen grains measure only 15 microns and pass easily through most windows.

References

Taxus cuspidata, the Japanese yew or spreading yew, is a member of the genus Taxus, native to Japan, Korea, northeast China and the extreme southeast of Russia.

It is an evergreen tree or large shrub growing to 10-18 m tall, with a trunk up to 60 cm diameter. The leaves are lanceolate, flat, dark green, 1-3 cm long and 2-3 mm broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flattish rows either side of the stem except on erect leading shoots where the spiral arrangement is more obvious.

Each seed cone contains a single seed, 4-8 mm in length, partially surrounded by a modified scaling, which eventually develops into an aril (8-12 mm in length, wide at the ends, and 8-12 mm in width). The arils are mature 6-9 months after pollination. Sikhote-Alin trees are estimated to be over 1,000 years old.

Uses

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity

The entire yew bush, except the aril (the red flesh of the berry covering the seed), is toxic due to a group of chemicals called taxine alkaloids. They cause an increase in the cytoplasmic calcium currents within myocardial cells and are well-known for their cardiotoxicity. These alkaloids are most concentrated in the seeds. It is important to seek immediate medical attention if any of the leaves or seeds are eaten. Also, it is recommended that you keep an eye on the area for at least six hours following the ingestion. The most cardiotoxic taxine is Taxine B followed by Taxine A; Taxine B also happens to be the most common alkaloid in the Taxus species. Yew poisonings are relatively common in both domestic and wild animals who consume the plant accidentally. Taxine alkaloids are quickly absorbed from the intestine. In large enough amounts, they can cause cardiac failure, respiratory failure, or cardiac arrest. Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves. Taxus Baccata leaves have approximately 5 mg taxines per 1g. The estimated (i.e. The estimated (i.e. Taxine remains in the plant all year, with maximal concentrations appearing during the winter. The toxicity of dried yew plant material can be retained for many months, and it may even increase as the water is removed. Fallen leaves are also toxic. Although poisoning usually occurs when leaves of yew trees are eaten, in at least one case a victim inhaled sawdust from a yew tree.

The book that follows made clear that it was very difficult to measure the taxine alkaloids. This is why there are so many different results.
Minimum lethal dose, oral LD_min for many different animals were tested:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horses 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

For symptoms of human toxicity see Taxine alkaloids

Male and monoecious yews in this genus release toxic pollen, which can cause the mild symptoms see Taxine alkaloids. The pollen are also a trigger for asthma. These pollen grains measure only 15 microns and pass easily through most windows.

References

Taxus Cuspidata is the Japanese Yiw (or spreading Yiw) and is a member the genus taxus. It’s native to Japan, Korea and the extreme southeast corner of Russia.

The evergreen shrub or tree can grow to 10-18m high and have a trunk of up to 60cm. The leaves are lanceolate, flat, dark green, 1-3 cm long and 2-3 mm broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flattish rows either side of the stem except on erect leading shoots where the spiral arrangement is more obvious.

Each seed cone contains a single seed, 4-8 mm in length, partially surrounded by a modified scaling, which eventually develops into an aril (8-12 mm in length, wide at the ends, and 8-12 mm wide). The arils are mature 6-9 months after pollination. Sikhote-Alin trees are estimated to be over 1,000 years old.

Uses

It is widely grown in eastern Asia and eastern North America as an ornamental plant.

Toxicity

The entire yew bush, except the aril (the red flesh of the berry covering the seed), is toxic due to a group of chemicals called taxine alkaloids. Their cardiotoxicity is well known and act via calcium and sodium channel antagonism, causing an increase in cytoplasmic calcium currents of the myocardial cells. The seeds contains the highest concentrations of these alkaloids. If any leaves or seeds of the plant are ingested, urgent medical advice is recommended as well as observation for at least 6 hours after the point of ingestion. The most cardiotoxic taxine is Taxine B followed by Taxine A; Taxine B also happens to be the most common alkaloid in the Taxus species. Yew poisonings are relatively common in both domestic and wild animals who consume the plant accidentally. Taxine alkaloids are quickly absorbed from the intestine. In large enough amounts, they can cause cardiac arrest, general cardiac failure, or respiratory failure. Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves. Taxus Baccata leaves have approximately 5 mg taxines per 1g. The estimated (i.e. The estimated (i.e. Taxine is found in the plant throughout the year. The highest concentrations are seen during winter. Dried yew plant material retains its toxicity for several months and even increases its toxicity as the water is removed, fallen leaves are also toxic. Although poisoning usually occurs when leaves of yew trees are eaten, in at least one case a victim inhaled sawdust from a yew tree.

The following book made it clear that it is very difficult to measure taxine alkaloids and that this is a major reason as to why different studies show different results.
Tests of the minimum lethal dose, oral _min and for many other animals were done:

Chicken 82.5 mg/kg

Cow 10.0 mg/kg

Dog 11.5 mg/kg

Goat 60.0 mg/kg

Horses 1.0-2.0 mg/kg

Pig 3.5 mg/kg

Sheep 12.5 mg/kg

Several studies have found taxine LD₅₀ values under 20 mg/kg in mice and rats.

See Taxine alkaloids for symptoms of toxic human reactions

Male and monoecious yews in this genus release toxic pollen, which can cause the mild symptoms see Taxine alkaloids. The pollen are also a trigger for asthma. These pollen grains are only 15 microns in size, and can easily pass through most window screens.

References