Canellales Plant Order
qiazhan English name: Canellales
Sub Title:
Canellales, formerly called Winterales, order of flowering plants consisting of 2 families (Winteraceae and Canellaceae), 15 genera, and 136 species. Together with three other orders (Laurales, Magnoliales, and Piperales), Canellales constitutes the magnoliids clade, which is an early branch in the angiosperm tree.
Distribution and abundance
Winteraceae has 9 genera and 120 species, with a mostly Southern Hemisphere distribution. Takhtajania, a genus with a single species (T. perrieri), occurs in Madagascar and is the most distinctive member of the family. Pseudowintera (3 species) is restricted to New Zealand. Drimys (about 8 species) occurs in Central and South America, from Mexico to Tierra del Fuego; one species is restricted to the Juan Fernández Islands off the coast of Chile, where it is one of the most common forest trees. Molecular research supports the separation of the Old World members of Drimys into the genus Tasmannia (with about 40 species), which extends from the Philippines to Australia (including Tasmania) and reaches its greatest diversity in New Guinea. The circumscription of Zygogynum has led to the recognition of 3 additional genera, including Exospermum (restricted to New Caledonia), Bubbia (from the Moluccas to New Caledonia and Australia, with one species confined to Lord Howe Island, where it is abundant), and Belliolum (in New Caledonia and the Solomon Islands).
Canellaceae has 6 genera and 16 species. There is one genus each in tropical Africa (Warburgia) and Madagascar (Cinnamosma), two genera in tropical South America (Capsicodendron and Cinnamodendron), and two in the Caribbean (Canella and Pleodendron).
Economic and ecological importance
Most members of Winteraceae have little economic importance. Drimys winteri variety chilensis is cultivated in many parts of the world in gardens and arboretums. A small bushy tree in cultivation, it flowers for most of the year and has attractive white-petaled flowers that are about 2.5 cm (1 inch) in diameter. The species name refers to Capt. John Winter, who obtained specimens in 1578 from the Strait of Magellan on Sir Francis Drake’s voyage around the world. The bark was once used by sailors as a tonic and as a scurvy preventative. It still has some use as an astringent and a stimulant.
The leaves of many Winteraceae have a peppery taste, which discourages browsing animals. In parts of New Zealand, where introduced deer have had serious effects on the shrubs and young trees in native forests, Pseudowintera has increased because it is unpalatable to deer.
The family Canellaceae is also of relatively little economic importance. The leaves and bark of the West Indian Canella alba (wild cinnamon), known sometimes by the synonym C. winterana, have some use as a condiment and for medicinal purposes. It has been used to flavour tobacco and as a fish poison. The timber is known as Bahama whitewood. The trees of this species are cultivated to a limited extent in southern Florida as ornamentals prized for their reddish purple flowers and red berries.
Characteristic morphological features
Winteraceae are evergreen trees and shrubs with alternately arranged leaves and primitively vesselless wood. To restrict transpiration, most species of Winteraceae grow in damp, shady habitats, and their stomata (restricted to the underside of the leaves) are partly obstructed by a somewhat porous, waxy material (cutin) that resembles a sponge under high magnification. Except in Tasmannia, the flowers are bisexual with a small cup of sepals fused to varying degrees and spirally arranged mostly white petals. One member, Belliolum, has leaflike stamens somewhat similar to Degeneria (family Degneriaceae). Except in Belliolum, the stamens have terminal pollen sacs, and, except in a few species of Zygogynum, the distinctive pollen is in tetrads with reticulate sculpturing on the exposed surface. The carpels may be free from each other or fused together, and most fruit of the family is indehiscent and berrylike. Pollination in various members of Winteraceae is carried out by beetles, primitive moths, flies, thrips, and even caterpillars.
Members of the family Canellaceae have leathery alternate leaves, commonly with translucent spots. The flowers contain 3 sepals, 4 to 12 petals (either arranged in a spiral or a whorl), and 6 to 40 stamens, which are united into a tube, a characteristic feature for the family. The pollen has only a single aperture. Between two and six carpels are fused to form a single locule in which the ovules are attached to the inner surface of the locule wall (parietal placentation). The fruit is a berry.
Evolution
Winteraceae has a fossil record dating to the Aptian Stage (125 million to 113 million years ago) in the Cretaceous Period (145.5 million to 65.5 million years ago). The minute, relatively undifferentiated embryo, which occupies only a small part of the seed at maturity, and the vesselless wood of Winteraceae species are generally interpreted as a primitive character. The stamens range from a putatively primitive leaflike form (Belliolum) to more-advanced forms having an elongated filament and terminal anther (Tasmannia). Takhtajania perrieri is unusual in the family in apparently having a flower with an ovary consisting of two fused carpels with peripheral ovules.
