| Taxus cuspidata | |
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Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Gymnospermae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Cupressales |
| Family: | Taxaceae |
| Genus: | Taxus |
| Species: | T. cuspidata |
| Binomial name | |
| Taxus cuspidata | |
Taxus cuspidata, the Japanese yew [2] or spreading yew, is a member of the genus Taxus , native to Japan, Korea, northeast China and the extreme southeast of Russia.
In Japan, the tree is known as ichi'i (一位), meaning "first rank". This is because first rank courtiers carried shaku scepters made of yew. Other Japanese names include jakunoki, araragi, and onko. In the Ainu language, it is called rarmani.
In China, it is called dongbei hongdoushan (東北紅豆杉 "northeastern red bean fir"), zishan (紫杉 "purple fir"), or chi bo song (赤柏松 "red cypress-pine").
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. The arils are mature 6–9 months after pollination.
Japanese yew is a long-lived tree. Individual trees from Sikhote-Alin are known to have been 1,000 years old. [3]
One specimen in Tottori, Japan, known as Sentsūzan-no-Ichii ("Yew of Mount Sentsū") is estimated at 2,000 years old. [4]
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. [5] [6] 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. [7] [8] 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. [6] [9] [10]
Yew poisonings are relatively common in both domestic and wild animals who consume the plant accidentally. [11] [12] [13] 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. [14] Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves. [15] Taxus baccata leaves contain approximately 5 mg of taxines per 1g of leaves. [9] The estimated (i.e. not by any means a fact) lethal dose (LDmin) of Taxus baccata leaves is 3.0-6.5 mg/kg body weight for humans [16] There is currently no known antidotes for yew poisoning, but drugs such as atropine have been used to treat the symptoms. [17] 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, [18] fallen leaves are also toxic. [19] Although poisoning usually occurs when leaves of yew trees are eaten, in at least one case a victim inhaled sawdust from a yew tree. [20]
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. [21] Minimum lethal dose, oral LDmin for many different animals were tested:
Several studies [22] 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. [23]
The tree is widely grown in eastern Asia and eastern North America as an ornamental plant.
Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta, also known as Coniferophyta or Coniferae. The division contains a single extant class, Pinopsida. All extant conifers are perennial woody plants with secondary growth. The great majority are trees, though a few are shrubs. Examples include cedars, Douglas-firs, cypresses, firs, junipers, kauri, larches, pines, hemlocks, redwoods, spruces, and yews. As of 2002, Pinophyta contained seven families, 60 to 65 genera, and more than 600 living species.
Taxus is a genus of coniferous trees or shrubs known as yews in the family Taxaceae. Yews occur around the globe in temperate zones of the northern hemisphere, northernmost in Norway and southernmost in the South Celebes. Some populations exist in tropical highlands.
Taxaceae, commonly called the yew family, is a coniferous family which includes six extant and two extinct genera, and about 30 species of plants, or in older interpretations three genera and 7 to 12 species.
An aril, also called an arillus, is a specialized outgrowth from a seed that partly or completely covers the seed. An arillode or false aril is sometimes distinguished: whereas an aril grows from the attachment point of the seed to the ovary, an arillode forms from a different point on the seed coat. The term "aril" is sometimes applied to any fleshy appendage of the seed in flowering plants, such as the mace of the nutmeg seed. Arils and arillodes are often edible enticements that encourage animals to transport the seed, thereby assisting in seed dispersal. Pseudarils are aril-like structures commonly found on the pyrenes of Burseraceae species that develop from the mesocarp of the ovary. The fleshy, edible pericarp splits neatly in two halves, then falling away or being eaten to reveal a brightly coloured pseudaril around the black seed.
Conium is a genus of flowering plants in the family Apiaceae. As of December 2020, Plants of the World Online accepts six species.
Strychnos nux-vomica, the strychnine tree, also known as nux vomica, poison fruit, semen strychnos, and quaker buttons, is a deciduous tree native to India and to southeast Asia. It is a medium-sized tree in the family Loganiaceae that grows in open habitats. Its leaves are ovate and 5–9 centimetres (2–3.5 in) in size. It is known for being the natural source of the extremely poisonous compound strychnine.
Taxus baccata is a species of evergreen tree in the family Taxaceae, native to Western Europe, Central Europe and Southern Europe, as well as Northwest Africa, northern Iran, and Southwest Asia. It is the tree originally known as yew, though with other related trees becoming known, it may be referred to as common yew, European yew, or in North America English yew. It is a woodland tree in its native range, and is also grown as an ornamental tree, hedge or topiary. The plant is poisonous, with toxins that can be absorbed through inhalation, ingestion, and transpiration through the skin. Consuming any part of the tree, excluding the aril, can be deadly and the consumption of even a small amount of the foliage can result in death.
Torreya is a genus of conifers comprising six or seven species placed in the family Taxaceae, though sometimes formerly placed in Cephalotaxaceae. Four species are native to eastern Asia; the other two are native to North America. They are small to medium-sized evergreen trees reaching 5–20 m, rarely 25 m, tall. Common names include nutmeg yew.
Pseudotaxus chienii, the whiteberry yew, is a species of plant in the yew family, Taxaceae. It is the sole species in the genus Pseudotaxus, but closely related to the other yews in the genus Taxus. It is endemic to southern China, occurring in northern Guangdong, northern Guangxi, Hunan, Southwest Jiangxi and southern Zhejiang.
Austrotaxus spicata, the New Caledonia yew or southern yew, is a species of yew, the sole species in the genus Austrotaxus. It is related to the other yews in the genera Taxus and Pseudotaxus.
Taxus brevifolia, the Pacific yew or western yew, is a species of tree in the yew family Taxaceae native to the Pacific Northwest of North America. It is a small evergreen conifer, thriving in moisture and otherwise tending to take the form of a shrub.
Taxanes are a class of diterpenes. They were originally identified from plants of the genus Taxus (yews), and feature a taxadiene core. Paclitaxel (Taxol) and docetaxel (Taxotere) are widely used as chemotherapy agents. Cabazitaxel was FDA approved to treat hormone-refractory prostate cancer.
Taxus canadensis, the Canada yew or Canadian yew, is a conifer native to central and eastern North America, thriving in swampy woods, ravines, riverbanks and on lake shores. Locally called simply as "yew", this species is also referred to as American yew or ground-hemlock.
Taxus wallichiana, the Himalayan yew, is a species of yew, native to the Himalaya and parts of south-east Asia. The species has a variety of uses in traditional medicine. It is currently classified as endangered by the IUCN.
Taxus floridana, the Florida yew, is a species of yew, endemic to a small area of under 10 km² on the eastern side of the Apalachicola River in mesophytic forests of northern Florida at altitudes of 15–40 m. It is listed as critically endangered. It is protected in reserves at the Torreya State Park and at the Nature Conservancy's Apalachicola Bluffs and Ravines Preserve, and has legal protection under the United States and Florida Endangered Species laws.
Conium maculatum, known as hemlock, or poison hemlock is a highly poisonous flowering plant in the carrot family Apiaceae, native to Europe and North Africa. It is herbaceous without woody parts and has a biennial lifecycle. A hardy plant capable of living in a variety of environments, hemlock is widely naturalised in locations outside its native range, such as parts of Australia, West Asia, and North and South America, to which it has been introduced. It is capable of spreading and thereby becoming an invasive weed.
Yew is a common name given to various species of trees.
Taxine alkaloids, which are often named under the collective title of taxines, are the toxic chemicals that can be isolated from the yew tree. The amount of taxine alkaloids depends on the species of yew, with Taxus baccata and Taxus cuspidata containing the most. The major taxine alkaloids are taxine A and taxine B although there are at least 10 different alkaloids. Until 1956, it was believed that all the taxine alkaloids were one single compound named taxine.
Taxus × media, sometimes known simply as Taxus media, is a conifer created by the hybridization of English yew Taxus baccata and Japanese yew Taxus cuspidata. This hybridization is thought to have been performed by the Massachusetts-based horticulturalist T.D. Hatfield in the early 1900s.
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