So what are these plants that are unique to the Himalayas? According to many internet sources (e.g. the website of the Critical Ecosystem Partnership Fund, http://www.cepf.net) there are five plant families endemic to the region; the Tetracentraceae, Hamamelidaceae, Circaesteraceae, Butomaceae and Stachyuraceae. But, though this information is repeated widely, it is not quite right….
The smallest family mentioned, the Butomaceae, comprises just one species – the aquatic Butomus umbellatus or flowering rush. This is hardly endemic to the Himalayas; it is native to the UK as well as the Himalayas (see Francis Rose’s The Wild Flower Key), and a swathe of areas between. In fact, Butomus illustrates well how a plant may be endangered in parts of its range but a nuisance in others. Introduced in North America as an ornamental, it is now an invasive weed in the some of the Great Lakes.
Butomus umbellatus: Image via Wikimedia commons
The other four families described as endemic, apart from the Hamamelidaceae, are also very small, containing just a handful of species. Not all of these are found in the parts of Kashmir and Ladakh which we will be visiting, either.
The Tetracentraceae comprises just two living tree species; Tetracentron sinense (from southern China and the eastern Himalayas) and Trochodendron aralioides (from Japan), known as the cartwheel tree. Again, the family as a whole could hardly be described as Himalayan endemics! The interesting thing for a botanist about these species is that they lack the efficient, water-transporting vessel elements in their xylem tissue which typify most angiosperms. More unusually, this feature seems to have evolved as a secondary character, rather being an indication of the primitive status of the family, as previously thought.
Trochodendron aralioides: Image via Wikimedia commons
The Hamamelidaceae is a much larger family of around 30 genera and 232 species (www.theplantlist.org) but only a few of these occur naturally in the Himalayas. Also shrubs and trees, the Hamamelidaceae may be more familiar as Witch-hazels, named for their pliable twigs (from the Middle English wiche). The twigs of Parrotiopsis jacquemontiana, found in the western Himalayas at altitudes between 1200 and 2800 m, are traditionally used for both rope and basket-making.
Image via Wikimedia commons
There seems less difficulty in describing the final two families as being endemic to the Himalayas, or at least the broad region. The Circaesteraceae is a family of flowering herbs containing just two species, Circaeaster agrestis and Kingdonia uniflora. Only C. agrestis is found in the northwest Himalayas; a shade plant of forests and wet grasslands, it can survive at altitudes of up to 5000 m.
Photo credit: DE Boufford, efloras.org
The last of the five ‘endemic’ families, the Stachyuraceae, has just a single genus, Stachyurus, but a number of species. These are deciduous shrubs and trees with attractive pendent racemes of flowers which appear before the leaves. Because of this, Species such as Stachyurus praecox make popular garden plants in the UK.
Image via Wikimedia commons
One thing that has become clear very quickly, on researching the flora of the Himalayas, is the lack of clarity over what constitutes an endemic plant family. In addition, there is the much larger question of the reliability of information circulating on the internet in official-looking guises and how often this is taken up and repeated, without thought. Plenty to ponder in subsequent posts….