Monday, 14 October 2013

Taxon of the Day: Hamamelis

Hamamelis virginiana
Last month’s Catalogue of Life Dynamic Checklist saw the arrival of many new Global Species Databases including one that contains the genus Hamamelis in the plant family Hamamelidaceae. This taxon includes the species H. virginiana L. (Witch-hazel),  H. vernalis Sarg. (Springtime Witch-hazel) and H. ovalis S.W. Leonard (Big Leaved Witch-hazel) all found in North America, H. japonica  Sieb. & Zucc. (Japanese Witch-hazel) from Japan and H. mollis Oliv. (Chinese Witch-hazel) from China. As a result of the new Global Species Database (GSD) the Catalogue of Life Dynamic Edition now lists all the above species. However, the Annual Checklist updated once-per-year currently lists just four. This is because prior to the new GSD's arrival Hamamelis was formed using a proto-GSD that combined ITIS Regional database (covering North America) with the Catalogue of Life China database. This meant H. japonica, not found in either of these locations, was unfortunately excluded. Next year all five species will be in the Annual Checklist in addition to the Dynamic Checklist as a result of the new GSD.

A deciduous shrub or small tree with a short trunk, Witch-hazel bears many spreading, twisted branches. Because of its ability to flower at a time when other plants are dormant, it is a widely grown garden plant with many known cultivars. It reproduces mainly by seed and has capsules that burst open explosively when mature, launching their contents a fair distance from the parent plant.

The species we have here at Reading University in the Harris Garden is H.virginiana which is now showing some beautiful autumnal colour. Soon the red leaves will drop off leaving the branches bare as if ready for winter, but before long they will burst out into bright yellow, twisted ribbon-like flowers. If you can’t wait or are unable to see it, this time-lapse video below does a good job of recording this event albeit with a Hamamelis cultivar elsewhere.

The etymology of the species epithets describe different aspects of its appearance, distribution or flowering time. Where japonica means from Japan and virginiana is Latin for Virginia, probably a result of its native eastern North American distribution. Then mollis in Latin means "soft" referring to the felted leaves of this species, and vernalis translates to spring in Latin, referring to the later flowering time of this species.  Finally, ovalis means oval, a likely reference to the shape of the leaves. The common name comes from the historical use of the twisted branches as ‘witching sticks’ used as dowsers in the search for water. Hazel describes the resemblance of the leaf shape to those of the hazelnut (ie Corylus).

Hamamelis or Witch-hazel has a well-known eponymously named homeopathic remedy, where extracts, lotions, salves are produced from the bark, twigs and leaves of the plant. For centuries it was used to cure a whole range of bodily ills but mainly these days is used for minor problems such as bruises, sores and inflammations. This is because the used parts of the plant contain compounds which reportedly have astringent, anti-irritant, antioxidant, and anti-inflammatory properties.

The species H. ovalis  was quite recently described to science (2004), which at that time in the plant world was almost the equivalent of finding a new species of mammal. For a detailed account of its discovery see the following web page.

CoL Dynamic Checklist: Search on Hamamelis 
CoL contributor: World Plants
Image copyright: By Jason Hollinger [CC-BY-2.0], via Wikimedia Commons

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