Winteraceae

Winter bark ( Drimys winteri )

The Winteraceae are a family of plants Magnoliids. It is characterized mainly by the absence of tracheae.

• 4.1 Notes and references

Features

Habit and stem

The Winteraceae are trees and shrubs. The nodes are bilakunär with three leaf traces, possibly trilakunär. An internal phloem is present. An important feature of the family is that it has no tracheae in the xylem. The sieve tube plastids belong to the S- type.

The leaves are spirally, rarely almost bubbly. They are stalked and weichlaubig to coriaceous. They have glands, no hair. They are simple with ganzrandiger leaf blade, the venation is feathery. The stomata are paracytisch. In the mesophyll cells are round to using essential oils, making the leaves were fragrant. Furthermore, there are sclerenchymatous idioblasts in the mesophyll. The minor leaf veins have no phloem transfer cells.

Inflorescences and flowers

Most species are hermaphroditic. Pollination is by wind ( anemophily ) or by insects ( entomophily ).

The flowers appear singly or in zymösen inflorescences. The flowers are of medium size. The perianth is divided into calyx and corolla. The calyx consists of two to four (six) sepals in a flower circle that are at least partially intergrown and form a calyptra ( flowers cover). The (two) five to 50 petals are i one to three circles. The the outermost circle are sometimes partly covered.

The stamens are free in two to five circles. They are created centripetal, but mature centrifugal. There are 15 to 100 stamens, which are all fertile. They are often flat, rarely filiform. The anthers are adnat and open with a longitudinal slot. The anther has two to four cell layers. The pollen is spread in aggregates or singly, usually in tetrads. The pollen grains are monoporat or trichotomocolpat, and two-celled.

The gynoecium consists of ( a ) three to 20 carpels in a flower circle. They are upper constant. The carpels are closed completely or incompletely. In most cases the carpels are not fused together ( apokarp ), but can also be grown ( synkarp ). A stylus can be formed. One to 100 ovules in marginal or disperse placentation are trained per carpel. In carpels of the ovary consists of two to 20 subjects and has just as many scars, and one to 50 ovules per subject.

The ovules are anatrop, bitegmisch and crassinucellat. The embryo sac corresponds to the Polygonum type. The polar nuclei fuse before fertilization. The three antipodal cells are retained. The endosperm is cellular.

Fruits

The fruits are berries or capsules. There can be multiple fruits. The endosperm is smooth and oily. The embryo is well differentiated, but very small.

Chemical properties

Proanthocyanidins, flavonols and cyanidin occur regularly. Cyanogenic glycosides and alkaloids are partially available. Iridoids and ellagic acid are missing.

Dissemination

The Winteraceae are located in the temperate to tropical latitudes, especially in the mountainous regions of the tropics. They are from Malaysia to the Pacific, to be found in eastern Australia and New Zealand, but also in Central and South America, as well as in Madagascar.

System

There are four to seven genera, according to sources. The eponymous for the family genus Wintera is now incorporated into Pseudowintera. After Kew Gardens there are the following four genera:

• Drimys J.R.Forst. . & G.Forst, with about 9-21 species ( about 5-14 Asian species are often separated as a distinct genus Tasmannia R. Br ex DC from four to seven South American Drimys species. ); including: Winter bark (. Drimys winteri JR Forst & G. Forst. ), Origin: Chile and Argentina

• Takhtajania perrieri ( Capuron ) Baranova & J.-F. Leroy is often placed in its own subfamily Takhtajanioideae or even their own family Takhtajaniaceae

Other genera:

• . Bubbia Tiegh, with only one type, but which is also found to Zygogynum: Bubbia howeana (F. Muell. ) Tiegh. ; it is found only on Lord Howe Island east of Australia

• Exospermum stipitatum ( Baill. ) Tiegh.

Sources and further information

The article is based primarily on the following links:

• Winteraceae on the APWebsite (English )
• Winteraceae in L. Watson and M. J. Dallwitz (1992 onwards ), The families of flowering plants
• David J. Mabberley: The Plant-Book. A portable dictionary of the higher plants. Cambridge University Press, Cambridge, among other things, 1987, ISBN 0-521-34060-8.
• Walter Erhardt, Erich Götz, Nils Boedeker, Siegmund Seybold: The big walleye. Encyclopedia of plant names. Volume 2: Types and varieties. Eugen Ulmer, Stuttgart 2008, ISBN 978-3-8001-5406-7.