Canadian dogwood

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Canadian dogwood
Canadian dogwood (Cornus canadensis), illustration

Canadian dogwood ( Cornus canadensis ), illustration

Systematics
Nuclear eudicotyledons
Asterids
Order : Dogwood-like (Cornales)
Family : Dogwood family (Cornaceae)
Genre : Dogwood ( Cornus )
Type : Canadian dogwood
Scientific name
Cornus canadensis
L.

The Canadian dogwood ( Cornus canadensis ) is a species of the dogwood ( Cornus ) genus . The distribution area extends from eastern Canada over all of northern North America to Alaska and eastern Siberia . It is occasionally used as an ornamental plant.

description

The Canadian dogwood is a perennial herbaceous plant . The shoots formed annually, depending on the location, arise from a branched rhizome around the beginning of June and reach heights of growth of around 10 to 30 centimeters. Due to the underground rhizome, it often forms large carpets.

The leaves at the end of the stems of four or six together in a whorl. The leaves are oval and pointed. In the similar Swedish dogwood , the leaves are evenly distributed over the entire stem. The stems end with an inflorescence or remain purely vegetative.

The inflorescence contains about eight to 25 flowers . The inflorescence is surrounded by four white, sometimes pink bracts . There are four white or greenish bracts . The flowers contain a nectar-secreting disc, they open from around July to August. A mechanism for ejecting the pollen has been observed in the Canadian dogwood: a delicate bristle is located on one of the flower bracts, which, when touched, causes the still closed flower to burst and the anthers to be thrown upwards via a joint. As a result, insects visiting the flower are dusted with pollen . If the flower opens without touching it, the wind carries the pollen that is thrown upwards.

The round, red berries ripen in September. They are non-toxic, but taste bland and floury. They are eaten by animals, which ensure the spread. The seed germinates in the following spring or after two winters.

The number of chromosomes is 2n = 22 or 44.

Distribution and ecology

Canadian dogwood is found widespread across Canada, eastern Siberia, and the northern states of the United States. To the south, isolated occurrences in the heights of the Rocky Mountains reach as far as New Mexico . The easternmost occurrence is in Greenland .

Different soils are populated, mostly in the undergrowth and clearings of coniferous forests. The Canadian dogwood tolerates a more continental and therefore drier climate than the Swedish dogwood , but mostly occurs in places with a good water supply. It often grows together with the moss bell ( Linnaea borealis ), the green-flowered wintergreen ( Pyrola chlorantha ), the dwarf raspberry ( Rubus pubescens ), the seven-star ( Trientalis borealis ) and the violet ( Viola renifolia ).

The Canadian dogwood is grazed by deer and elk , and its fruits are food for numerous birds and mammals.

Systematics

The Canadian dogwood is closely related to the Swedish dogwood. Hybrids occur where their ranges overlap. Stabilized, tetraploid hybrids are described as Cornus unalaschkensis ; these can also occur outside the current range of the parent species. The herbaceous dogwood species have been separated by some authors as a separate genus Chamaeperyclimenum , but are usually included in the genus Cornus .

swell

Individual evidence

  1. ↑ T. Mosquin: The explosive pollination mechanism in the pop flower Chamaepericlymenum Cornaceae . In: Canadian Field-Naturalist . tape 99 , no. 1 , 1985, pp. 1-5 .
  2. ↑ Cornus canadensis at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
  3. ^ Zack E. Murrell: Dwarf Dogwoods: Intermediacy and the Morphological Landscape . In: Systematic Botany . tape 19 , no. 4 , 1994, pp. 539-556 , doi : 10.2307 / 2419776 .

literature

  • Corey L. Gucker: Cornus canadensis. In: Fire Effects Information System, (Online). US Department of Agriculture, Forest Service, accessed July 5, 2019 .

Web links

Commons : Canadian Dogwood ( Cornus canadensis )  - Album containing pictures, videos and audio files