Opportunist species

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No-one enjoys traffic jams, that would be like looking forward to going to the dentist or hoping for higher taxes. Yet I found myself, earlier this week, supplicant before the great Gods of Traffic, asking for a jam… just a small one… in a particular place on the way to the University! Why this strangely aberrant behaviour? Well, this is a herbology blog and I wanted to get a close look at an unusual botanical success story.

In the warm spring sunshine it is easy to forget that three months ago Britain was in the grip of the coldest winter for more than a decade. Temperatures plummeted to -18 C in rural Cheshire, the University was closed for several days, and the landscape was blanketed in thick snow. Road salt was in heavy demand, and its use was concentrated on the motorways that the politicians insist oil the wheels of industry.

Three months later in the warm spring sunshine, swathes of starry white flowers have erupted along mile after mile of the M62 motorway. The story is repeated on many other motorways across the country. In some places there is almost a monoculture: white flowers stretch as far as the horizon.

Danish scurvy grass flowering on the central reservation of the M62 on the way to Manchester

The plant is Danish Scurvy Grass (Cochlearia danica), a saltmarsh species, which arrived in Britain in the Middle Ages. It is hardy and well adapted to hot, dry, and above all salty conditions. Danish Scurvy Grass flowers early in the year. It outcompetes native species in the roadside environment, where it tolerates the  salt produced by gritting.

Danish scurvy grass, cochlearia danica

Most Scurvy Grass specimens in the herbarium collection date from the nineteenth century. They are from locations such as Hilbre Island in the Dee Estuary and show that the plant was restricted to salty coastal environments at the time. Their distribution now also mirrors the British motorway and trunk road network, taking advantage of a habitat that simply didn’t exist in the nineteenth century. This illustrates one of the many uses of herbaria, mapping the changing distributions of plant species… as described in a previous post.


2 thoughts on “Opportunist species

    Anne Beswick said:
    May 4, 2010 at 3:10 pm

    Great story! I’m a Manchester Tourguide and I’m doing some “Trees” walks onMay 11, June 13, July 1st and Sept 5th. All at 2pm meeting at VIC, Lloyd St Manchester and “Botanical Manchester” June 18th, Aug 14th, 2.30pm Meet at Midland Hotel. All £6 (£5 concessions).
    I visited you and got some good ideas from Leander. I’ll include the Scurvy grass one to show how adaptable (or opportunistic) we are round here.
    Scurvy grass? Is it edible/high in Vit C?
    Also, cotton is I believe one of the mallow family. Is that right? How many petals per cotton flower. Just want to check they have it right around the Town Hall

      David Green responded:
      May 11, 2010 at 10:58 am

      Hello Anne,

      Hope this is useful…

      Scurvy-grass was extensively eaten in the past by sailors suffering from scurvy after returning from long voyages, as the leaves are rich in vitamin C, which cures this deficiency disease resulting from a lack of fresh vegetables in the diet. The leaves, which have a strong peppery taste similar to the related horseradish and watercress, are also sometimes used in salads

      It’s in the wild food books as well – It was taken on sea voyages to prevent scurvy until limes replaced it. It used as a medicinal herb until the last century. It was also eaten during the war to prevent scurvy as fresh fruit and veg was in short supply. Apparently it tastes either bitter or a combination of cucumber, mustard and cress and makes good sandwiches.
      Cotton is a member of the mallow family and has five petals. Four species are grown commerially:

      * Gossypium arboreum L. – Tree cotton, native to India and Pakistan.

      * Gossypium barbadense L. – known as American, Creole, Egyptian, or sea island cotton, native to tropical South America.

      * Gossypium herbaceum L. – Levant cotton, native to southern Africa and Arabian Peninsula.

      * Gossypium hirsutum L. – Upland cotton, native to Central America, Mexico, the Caribbean and southern Florida – most commonly grown species in the world.

      Best Wishes


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