Wednesday, April 27, 2011

Possible Legacy of Winter

With many trees showing full green coats, its becoming more difficult to remember the intense cold of last winter. Yet the scars can still be seen, be it gaping potholes in the tarmac of roads or the desolation of the Cordyline trees in many gardens (1). Worries of a lack of salt for the roads seem a little quaint now, as the warm days bring forth multitudes of insects. However as flowers seem to pop up overnight, the prospect of future cold winters may indirectly influence their future populations. Over 100,000 tonnes of salt were used on Irish roads during the 2010-'11 winter (2), making verges more suitable for plants usually associated with coastal habitats, plants better able to cope with high saline conditions. This is common throughout America and Europe and was first noted in 1982 in England (3), with the coastal plant common scurvy grass (Cochlearia offininalis) being added to a list of roadside plants for the first time.
Common Scurvy Grass, Cochlearia officinalis
C. officinalis should actually be seen as a species complex rather than a distinct, single species, with a number of different cytotypes present, each with a number of ecological distributions (4, 5). Interestingly, C. officinalis originated as a derivative of C. pyrenaica, and the origins of many Cochlearia spp. are as a result of changes in ploidy levels (6), demonstrating the role that polyploidisation plays in the evolution of new species.

  3. Scott and Davison, 1982. Watsonia 14 pp. 41-52
  4. Erikson and Nordal, 1989. Ecography 12 pp. 31-38
  5. Pegtel, 1999. Plant Species Biology 14 pp. 201-215
  6. Koch et al., 1998. Botanica Acta 111 pp. 411-425


  1. A long time ago I read that a certain plant native to the English West Country colonised the route of the Great Western Railway during the 19th century. This was due to the fact that this plant thrives in fire ash, of which the railway bed was a rich source. The plant species in question arrived in London just in time to colonise the bomb-sites, also rich in ash, which appeared there in 1940. I wonder what plant that was.

  2. Hi Peter,
    Thanks for the comment. I believe that the plant you are referring to is the Rosebay Willowherb (Chamerion augustifolium, also called Epilobium augustifolium). It earned its other common name "Fireweed" from its incredible colonisation abilities. Sparks from train wheels used to result in clearance of vegetation through fire of the areas alongside train tracks. Rosebay Willowherb (along with all Willowherb species) can produce a great number of windborne seeds which can immediately colonise vacant ground. Established populations spread even further by rhizome-spread. As you said, the plant also very successfully colonised bomb sites in London. Prior to this the plant was unknown in such urban settings. Nowadays it is also common on roadside verges, railway lines and in areas cleared within commercial coniferous plantations.