Wood sorrel ( Oxalis acetosella ), illustration
Appearance and leaves
The basic or alternate whorled or distributed to the stem axis arranged leaves are divided into petiole and leaf blade. The leaf blades are usually composed (fingered, threefold or pinnate). With some taxa, sleep or stimulus movements are carried out and the leaflets can be folded down. The leaf margin is always smooth. Stipules are absent or small.
Inflorescences and flowers
The flowers are arranged individually in the leaf axils or in dold-like , zymous or racemose inflorescences . The hermaphroditic flowers are radial symmetry and five-fold with a double flower envelope . The five sepals are free or at most fused at their base. The five petals are free or at most slightly fused at the base, sometimes they are clearly nailed. There are two circles with five stamens each. In most species, the stamens of the two circles have different lengths, with the stamens of the outer circle usually being shorter. The stamens can be fused at their base. There is often heterostyly , mostly tristyly. Five top permanent carpels are mostly one fünfkammerigen ovary grown in Biophytum they are more or less free. Each carpel rarely contains one, usually two to a few pendulous, anatropic or hemianatropic ovules in mostly central angular placentations , in the case of Biophytum in marginal placentation. Most of the five styles are free and each end in cephalic or short two-column scars.
Fruits and seeds
Loculicidal capsule fruits with different opening mechanisms or, more rarely, berries are formed. In species with capsule fruits, the seeds have a fleshy thickening of the epidermis at their base, which shrinks when drying, folds over and thereby hurls the seeds away. There is a fleshy, often oily endosperm .
The sorrel family occurs all over the world, except in very cold areas. However, their main distribution is in the tropics and subtropics.
They thrive in a variety of habitats from rainforests to deserts.
The first publication of this family under the name "Oxalideae" is Robert Brown : Narrative of an Expedition to Explore the River Zaire , 1818, p. 433. The type genus is Oxalis L. Taxa of the earlier family Averrhoaceae Hutch. belong today to the Oxalidaceae.
The wood sorrel family (Oxalidaceae) contains about five genera with about 780 species:
- Averrhoa L .: With two species in tropical Asia:
- Biophytum DC. : With about 50 species in the tropics and subtropics of the world.
- Dapania Korth. : With about three species, two of them in Malesia and one in Madagascar .
- Wood sorrel ( Oxalis L. ): With 700 to 800 species almost worldwide.
Sarcotheca DC. : With perhaps the only kind:
- Sarcotheca laxa (Ridl.) Knuth : It occurs in Malesia.
Some oxalis species and their varieties are used as ornamental plants .
- The family of Oxalidaceae in APWebsite. (Section description and systematics)
- Leslie Watson: Western Australian Flora , 2008: Oxalidaceae - Online. (Section description)
- Liu Quanru & Mark Watson: Oxalidaceae in der Flora of China , Volume 11, 2008, p. 1: Online. (Section description, distribution and systematics)
- Robert Hegnauer: Chemotaxonomy of plants: an overview of the distribution and the systematic importance of plant substances , Volume 9, Birkhäuser, 1990. ISBN 978-3-7643-2299-1 Google-Books-Online. Oxalidaceae pp. 182-184. (Section Ingredients and Usage)
- Entry in Tropicos .
- Oxalidaceae in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
- David John Mabberley: Mabberley's Plant-Book. A portable dictionary of plants, their classification and uses . 3rd ed. Cambridge University Press 2008. ISBN 978-0-521-82071-4 , page 769.