Rhus

from Wikipedia, the free encyclopedia
Rhus
Climbing poison sumac (Rhus radicans), illustration

Climbing poison sumac ( Rhus radicans ), illustration

Systematics
Rosids
Eurosiden II
Order : Sapindales (Sapindales)
Family : Sumac family (Anacardiaceae)
Subfamily : Anacardioideae
Genre : Rhus
Scientific name
Rhus
L.
Vinegar tree ( Rhus typhina )

The plant genus Rhus belongs to the sumac family (Anacardiaceae) and includes around 150 to 250 species. These include on the one hand the species of the former genus Toxicodendron , which are called poison sumac or sometimes also poison oak or poison ivy , and on the other hand many species that are known as sumac , for example the vinegar tree and the tanner sumac . Many types are of economic importance in the manufacture of tanning and coloring agents. All species are more or less poisonous and can cause skin irritation.

description

Vegetative characteristics

Rhus species are woody plants: the majority are deciduous or evergreen shrubs , less often lianas or small trees . They have fleshy roots . Most species carry milky sap . The alternate leaves are usually pinnate unpaired. The rachis is sometimes winged. The stalked or sessile leaflets have a serrated or smooth edge.

Generative characteristics

A majority of the species are dioeciously separated ( dioecious ), the rest are polygamous . Terminal and lateral, paniculate or thyrsoid inflorescences are formed. The flowers stand over durable or decrepit bracts. The relatively small, five-fold flowers are hermaphroditic or facultatively unisexual and have five petals and five stamens that arise under a brown discus . The unilocular ovary contains only one ovule . The three styles are often fused at their base.

Roundish or somewhat flattened, red drupes are formed when ripe , with a very hard endocarp , resinous, red mesocarp and thin exocarp , whereby the meso- and exocarp are fused. The seeds germinate epigeously and contain no endosperm (i.e. no nutrient tissue for the seeds).

Occurrence

The distribution area are the temperate and subtropical zones, especially in South Africa and the African Tropical Mountains, in West, Central and East Asia, North America, North Africa and Europe.

They occur on stony slopes and are resistant to frost and drought and need a lot of light.

Systematics

The genus name Rhus was Linnaeus in Species Plantarum , 1, 1753 pp 265-267 with several kinds first published . As lectotype was Rhus coriaria L. NL Britton & A. Brown in Ill. Fl. NUS , 2nd edition, 2, 1913, p. 481. A synonym for Rhus L. is Baronia Baker , Duckera F.A.Barkley , Malosma Nutt. ex Abrams , Melanococca flower , Neostyphonia Shafer , Schmaltzia Desv. ex Small , Schmalzia Desv. ex DC. , Searsia F.A.Barkley , Terminthia Bernh. , Toxicodendron Mill. , Trujanoa La Llave .

The generic name Rhus was already used by the Romans and is derived from the Greek rhous ῥοῦς, which was probably also borrowed by the Greeks from another Mediterranean language that is no longer comprehensible today. The Romans used rhus to designate the Gerbersumach ( Rhus coriaria ) which is widespread in the Middle East and was also called rhus Syriaca. In ancient times it was known as a herb and medicinal plant and as a supplier of tannins.

The genus Rhus belongs to the subfamily Anacardioideae within the family Anacardiaceae . The taxonomy of the genus has changed several times over time. Some authors differentiate between the genus Rhus and the genera Toxicodendron Mill. And Schmaltzia Desv. whose species are otherwise assigned to the genus Rhus . As a result, the number of species contained fluctuates considerably and is given with values ​​between 35 and 200.

According to Miller, the genus Rhus is divided into two sub-genera and several sections:

  • Subgenus Rhus : With about 10 species. The area is disjoint : North America (four species), East Asia (three species), Hawaii (one species), and Europe (one species).
  • Subgenus Lobadium (Raf.) A. Gray : With three sections and about 25 species. With areas from North America to Central America:
    • Section Lobadium (Raf.) DC.
    • Section styphonia
    • Section Sumac DC.

According to Rehder, only two sections are distinguished:

  • Section Sumac DC. , with flowers in terminal panicles, densely hairy, red fruits and pinnate leaves
  • Section Toxicodendron A. Gray , with axillary inflorescences and whitish to brownish, glabrous fruits

species

Of the 150 to 250 species, around 100 live in the extra-tropical areas of the northern and southern hemispheres, around 20 of them in temperate and semi-arid areas of North America, around 60 in temperate Asia and only three species in Europe. No species occurs naturally in Central Europe, but the vinegar tree ( Rhus typhina ) is often cultivated and found wild from culture.

Species of the genus Rhus

swell

  • Tianlu Min & Anders Barfod: Anacardiaceae in the Flora of China : Volume 11, 2008, p. 345: Rhus - Online. and Toxidodendron - Online
  • Tingshuang Yi, Allison J. Miller & Jun Wen: Phylogeny of Rhus (Anacardiaceae) based on sequences of nuclear Nia-i3 intron and chloroplast trnC-trnD. , In. Systematic Botany , 32, 2007, pp. 379-391.
  • AJ Miller, DA Young & J. Wen: Phylogeny and biogeography of Rhus (Anacardiaceae) based on ITS sequence data. In: Int. J. Plant Sci. , 162, 2001, pp. 1401-1407.
  • Schütt, Weisgerber, Schuck, Lang, Stimm, Roloff: Encyclopedia of Bushes , Nikol, Hamburg 2006, pp. 263–266, ISBN 3-937872-40-X
  • Schütt, Schuck, Stimm: Lexikon der Baum- und Straucharten , Nikol, Hamburg 2002, p. 445, ISBN 3-933203-53-8

Individual evidence

  1. ↑ Dr. Wesselin Denkow: Poisons of nature ; Ennsthaler Verlag, Seyr, 2004; ISBN 3-8289-1617-1 ; P. 110.
  2. ↑ Carl von Linné: Species Plantarum , 1, 1753, pp. 265-267 scanned in at biodiversitylibrary.org
  3. ^ Rhus in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland.
  4. ↑ Helmut Genaust: Etymological dictionary of botanical plant names. 3rd, completely revised and expanded edition. Nikol, Hamburg 2005, ISBN 3-937872-16-7 (reprint from 1996).
  5. ^ Fred A. Barkley and Elizabeth Ducker Barkley: A short history of Rhus to the time of Linnaeus. In: The American Midland Naturalist 19, (Notre Dame) 1938, No. 2, pp. 265–333.
  6. ↑ Miller et al .: Phylogeny and biogeography of Rhus (Anacardiaceae) based on ITS sequence data
  7. ^ A. Rehder: Manual of Cultivated Trees and Shrubs Hardy in North America , 2nd Edition, Dioscorides Press, Portland, OR. 1986, quoted from Schütt et al .: Encyclopedia of Shrubs

Web links

Commons : Rhus  - collection of images, videos and audio files