Walking beside the River Ouse from Clifton into York city centre yesterday, I took this shot of the trees across the river and the yellow flowers in the foreground. As I walked further I noticed many more of the yellow flowers, but it wasn't until I got into the city centre that I remembered - the flowers are tansy, and they are an important element in the life of the tansy beetle.
The tansy beetle appeared earlier in our project, around a year ago -
http://365project.org/fishers/365/2015-07-26 As I explained then, this beetle is very rare in the UK, only being found along a 30 mile section of the River Ouse around York.
Since then a project has been implemented to expand it's range by spreading the seeds of the Tansy plant further along the banks of the river, and I presume that is the reason for many more of these flowers being around on the river bank this year.
Wikipedia describes the tansy plant as follows - 'Tansy is a flowering herbaceous plant with finely divided compound leaves and yellow, button-like flowers. It has a stout, somewhat reddish, erect stem, usually smooth, 50–150 cm (20–59 in) tall, and branching near the top. The leaves are alternate, 10–15 cm (3.9–5.9 in) long and are pinnately lobed, divided almost to the center into about seven pairs of segments, or lobes, which are again divided into smaller lobes having saw-toothed edges, giving the leaf a somewhat fernlike appearance. The roundish, flat-topped, button-like, yellow flower heads are produced in terminal clusters from mid-to-late summer. The scent is similar to that of camphor with hints of rosemary. The leaves and flowers are toxic if consumed in large quantities; the volatile oil contains toxic compounds including thujone, which can cause convulsions and liver and brain damage. Some insects, notably the tansy beetle Chrysolina graminis, have resistance to the toxins and subsist almost exclusively on the plant.'
So there you are, an interesting glimpse of conservation at work!
Ian
Interesting tale. Those yellow flowers did look very familiar to me so I try google and yes, we know them by the name : Boerenwormkruid. They are common in our country.
Thank you all for your encouraging comments and favs, and for the extra information that you have provided.
Aparently tansy plants are quite common across Europe and Asia, and have been introduced in other parts of the world, including North America.
Tansy beetle is widespread in Europe, from Scandinavia to the Mediterranean Sea, but in the majority of countries the species is on the decline.
Ian