Taxusbaccata L. —English Yew
Taxus canadensis Marsh—Amenican yew
FAMILY: Taxaceae—the Yew Family
This group of evergreen shrubs and trees has leaves: needlelike, linear or scalelike, often appearing to be 2- ranked; plants: gymnosperms, but not producing female cones; seeds: surrounded by a hard coat and partly or completely surrounded by a fleshy aril.
PHENOLOGY: Inconspicuous flowers are produced early in the growing season; the conspicuous, scarlet fruits, late in the season.
DISTRIBUTION: Taxus baccata is cultivated and planted as an ornamental; more than 40 varieties and forms have been named. Taxus canadensis is a northern taxon found in coniferous forests, rich woods, thickets, and bogs. At least four cultivars are used horticulturally.
PLANT CHARACTERISTICS: The yews are popular shrubbery grown around the home for landscape value. They can be distinguished by long, slender, alternate dark, glossy green, flat needles and by the bright scarlet-red, fleshy cup covering the fruits.
POISONOUS PARTS: The entire plant contains poisonous alkaloids.
SYMPTOMS: Gastric distress, diarrhea, vomiting. tremors, dyspnea, dilated pupils, respiratory difficulties, weakness, fatigue, collapse, coma, convulsions, bradycardia, circulatory failure, and death are the result of ingestion. The toxins are rapidly absorbed by the intestines. Death is sometimes so rapid that few well-developed symptoms appear; survival after poisoning is rare. In Europe, yew is considered the most poisonous tree or shrub.
POISONOUS PRINCIPLES: The alkaloid mixture taxine is responsible for poisonings. Taxine I (major alkaloid) and taxine II (minor alkaloid) have been isolated from yews.
CONFUSED TAXA: No other woody, evergreen shrub or tree produces the characteristic bright ed, fleshy fruit with an opening at the terminal end.
SPECIES OF ANIMALS AFFECTED: Human fatalities due to cardiac and respiratory failure are known. Death in domestic animals is not uncommon. A fatal mistake can be made by placing branches in animal enclosures. Deer will also succomb to ingestion of yews.
TREATMENT: ( 11a)(b); (26); (5- definitely beneficial)
OF INTEREST: The red, fleshy aril is sweet and edible, at least in small quantities. Taxus has been used medicinally in the past. Taxus cuspidata Siebold & Zucc, a species related to those described above, has shown experimental hypoglycemic activity. The cancer chemotherapeutic drug taxol has been extracted from T. brevifolia Nutt. Toxicity may vary according to seasonal or geographic factors. All species in the genus should be considered potentially poisonous.