Taxaceae (/tækˈseɪsi.iː, -ˌaɪ/), 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.
Taxaceae (/tækˈseɪsi.iː, -ˌaɪ/), 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.
The order Pinales in the division Pinophyta, class Pinopsida, comprises all the extant conifers. The distinguishing characteristic is the reproductive structure known as a cone produced by all Pinales. All of the extant conifers, such as Araucaria, cedar, celery-pine, cypress, fir, juniper, kauri, larch, pine, redwood, spruce, and yew, are included here. Some fossil conifers, however, belong to other distinct orders within the division Pinophyta.
Multiple molecular studies indicate this order being paraphyletic with respect to Gnetales, with studies recovering Gnetales as either a sister group to Pinaceae or being more derived than Pinaceae but sister to the rest of the group.
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.
The oldest known fossil species are from the Early Cretaceous.
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.
The genus is one example of the Arcto-Tertiary Geoflora in paleoecology. The pattern of highly disjunct distribution of geographic ranges of the species within such a genus spans temperate plant zones of continents in the Northern Hemisphere. This geographic pattern is attributed to genus origins in much warmer times of the Tertiary Period, when zones of temperate climate were found in poleward latitudes whereby land connections facilitated range expansions and migrations of plants between Asia and North America and sometimes between Europe and North America.
Taxus baccata is an Old World species of evergreen tree in the family Taxaceae. It is the tree originally known as yew, though with other related trees becoming known, it is sometimes called common yew, European yew, or, in North America, English yew. It is a woodland tree in its native range, including much of Eurasia and Northwest Africa. All parts of the plant except the fleshy aril are poisonous, with toxins that can be absorbed through inhalation, ingestion, and transpiration through the skin.
The wood has been prized for making longbows and for musical instruments such as lutes. Yews are often grown as ornamental trees, hedges or topiaries, including in churchyards, where they sometimes reach great age; many explanations have been given for this planting, especially that the yew is associated with death, immortality, and rebirth. Multiple place names derive from the Proto-Celtic *eburos, but scholars disagree as to whether this meant the yew tree.
Cephalotaxaceae is a small family of conifers. It is often treated as a monophyletic family including only the single genus Cephalotaxus, while others have also included Torreya and Amentotaxus in the family. Cephalotaxaceae is closely allied to the yew family Taxaceae, and is often included in a wide interpretation of Taxaceae, based on phylogenetic evidence and close morphological similarities between them. Included species were restricted to east Asia, except for two species of Torreya found in the southwest and southeast of the United States; fossil evidence shows a much wider prehistorical Northern Hemisphere distribution. The most notable differences between Taxaceae and Cephalotaxaceae concerned the cone aril, which fully encloses the seeds of Cephalotaxaceae, the longer maturation of Cephalotaxaceae seeds and the larger size of the mature seeds.
When considered as a distinct family, members of Cephalotaxaceae are much branched, small trees and shrubs. The leaves are evergreen, spirally arranged, often twisted at the base to appear biranked. They are linear to lanceolate, and have pale green or white stomatal bands on the undersides. The plants are monoecious, subdioecious, or dioecious. The male cones are 4–25 mm long, and shed pollen in the early spring. The female cones are reduced, with one to a few ovuliferous scales, and one seed on each ovuliferous scale. As the seed matures, the ovuliferous scale develops into a fleshy aril fully enclosing the seed. The mature aril is thin, green, purple or red, soft and resinous. Each ovuliferous scale remains discrete, so the cone develops into a short stem with one to a few berry-like seeds. They are probably eaten by birds or other animals which then disperse the hard seed undamaged in their droppings, but seed dispersal mechanisms in the family are not yet well researched.