Cephalotaxaceae
Encyclopedia
The family Cephalotaxaceae is a small grouping of conifers, with three genera and about 20 species, closely allied to the Taxaceae
, and included in that family by some botanists. They are restricted to east Asia
, except for two species of Torreya
found in the southwest and southeast of the USA; fossil
evidence shows a much wider prehistorical northern hemisphere
distribution. The differences between the two families are as follows:
* To 25 mm in Austrotaxus
These are much branched, small tree
s and shrub
s. The leaves are evergreen
, spirally arranged, often twisted at the base to appear 2-ranked. 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 bird
s or other animal
s which then disperse the hard seed undamaged in their droppings, but seed dispersal mechanisms in the family are not yet well researched.
Taxaceae
The family Taxaceae, commonly called the yew family, includes three genera and about 7 to 12 species of coniferous plants, or in other interpretations , six genera and about 30 species....
, and included in that family by some botanists. They are restricted to east Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, except for two species of Torreya
Torreya
Torreya is a genus of conifers comprising five or six species, treated in either the Cephalotaxaceae, or in the Taxaceae when that family is considered in a broad sense. Four are native to eastern Asia; the other two are native to North America. They are small to medium-sized evergreen trees...
found in the southwest and southeast of the USA; fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
evidence shows a much wider prehistorical northern hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
distribution. The differences between the two families are as follows:
| Family | Taxaceae | Cephalotaxaceae |
|---|---|---|
| Cone aril | partly encloses seed | fully encloses seed |
| Cone maturation | 6-8 months | 18-20 months |
| Mature seed length | 5-8 mm * | 12-40 mm |
These are much branched, small tree
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
s and shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s. The leaves are evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
, spirally arranged, often twisted at the base to appear 2-ranked. They are linear to lanceolate, and have pale green or white stomatal bands on the undersides. The plants are monoecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
, subdioecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
or dioecious
Plant sexuality
Plant sexuality covers the wide variety of sexual reproduction systems found across the plant kingdom. This article describes morphological aspects of sexual reproduction of plants....
. The male cones
Conifer cone
A cone is an organ on plants in the division Pinophyta that contains the reproductive structures. The familiar woody cone is the female cone, which produces seeds. The male cones, which produce pollen, are usually herbaceous and much less conspicuous even at full maturity...
are 4-25 mm long, and shed pollen
Pollen
Pollen is a fine to coarse powder containing the microgametophytes of seed plants, which produce the male gametes . Pollen grains have a hard coat that protects the sperm cells during the process of their movement from the stamens to the pistil of flowering plants or from the male cone to the...
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
Aril
An aril is any specialized outgrowth from the funiculus that covers or is attached to the seed. It is sometimes applied to any appendage or thickening of the seed coat in flowering plants, such as the edible parts of the mangosteen and pomegranate fruit, the mace of the nutmeg seed, or the...
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
Berry
The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....
-like seeds. They are probably eaten by bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s or other animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...
s which then disperse the hard seed undamaged in their droppings, but seed dispersal mechanisms in the family are not yet well researched.