Oxydendrum

Sauer Tree ( Oxydendrum arboreum )

The sour tree ( Oxydendrum arboreum ) is the only species of one genus of the tribe Oxydendrum Oxydendreae that belongs to the family of the heather family ( Ericaceae ). The trivial names in the German Sauerland tree, in English " Sourwood " and the botanical genus name Oxydendrum - Greek: oxy for sour and dendron for tree - refer to the sour -tasting leaves.

Description

The sour tree is deciduous, medium-sized trees (life-form: Phanerophyt ) and can reach heights of growth of about 12 to 15 meters. This slow-growing species is shade tolerant but will also deal in sunny locations. The rusty - brown bark is initially smooth and is then cracked. The change-constant leaves are simple, 10-18 cm long and variable in shape. The leaf margin is smooth to cut. It is striking scarlet red in autumn the foliage. After a fire occurs, a new growth from the rootstock or from the trunk.

At the ends of branches (terminal) standing together a few racemose inflorescences part in 20 to 25 centimeters long, paniculate inflorescences total. There are bracts and in pairs standing bracts present. The stalked, sweet smelling, five petals are hermaphroditic and radial symmetry. The five sepals are fused at their base. The white, about 8 mm long petals are bell-shaped fused with only short Kronlappen. There are two circles, each with five fertile stamens present. The straight stamens and anthers tetrasporangiaten each have no appendages. Five carpels are fused into a superior ovaries. The lily of the valley -like inflorescences bloom in late summer June to August.

It is the only species within the Ericaceae, which has an oblong- ovoid capsule fruit; it is 6 to 13 mm long. The capsule fruit contains many tiny seeds (a report writes 4080000-12250000 seeds / kg). The capsule fruits ripen in the same year as the bloom from September to October, open in the winter and then dismissed the seeds do not all at once.

Ecology

The white-tailed deer (Odocoileus virginianus) eats the young branches.

Oberea tripunctata and Oncideres cingulata attack the branches. Hyphantria cunea and the larva of Citheronia regalis eat the leaves.

Occurrence

The sour tree comes from the eastern United States. The main distribution area ranges from 30 to 40 ° N and 75-92 ° W. The largest trees of this species growing on the western slopes of the Great Smoky Mountains in Tennessee. It becomes more acidic soil is preferred ( this species occurs at pH 4 to 6 dogs ). This species is hardy in Central Europe ( Hardiness: USDA climate zones 5-9).

Use

The reddish- brown, hard and heavy wood is not used very often. It manufactures thereof tool handles and uses it as firewood.

Sauer tree is used for spice mixtures. The flowers are important for honey extraction.

The acidic leaves are eaten raw. Medical uses have been investigated.

Especially due to its beautiful autumn colors of the sour tree is used as ornamental tree.

Swell

• Oxydendreae at Ericaceae Homepage of Kathleen A. Kron.
• USDA data sheet.
• Kathleen A. Kron, WS Judd, PF Stevens, DM Crayn, AA Anderberg, PA Gadek, CJ Quinn & JL Luteyn: A phylogenetic classification of Ericaceae: . Molecular and morphological evidence in Botanical Review, 68, 2002, pp. 335 - 423 ( Summary )