Fasciation

How often, as we queue at a Tesco checkout, have our minds turned to the matter of fasciation. Indeed, in Daventry we speak of little else. Well, perhaps I exaggerate a little, but it is a curiosity familiar to most gardeners. Fasciation is described in botanical works as  'a malformation of plant stems commonly manifested as enlargement and flattening as if several stems were fused.' Little is offered in the way of explanation for these odd distortions.


A Gaillardia with the flower head displaying fasciation.

Daventry market. 4 July, 2017

On Daventry market a while back a Gaillardia showed a distorted flower head, the normally round disk florets having taken up an oval shape. This was the result of the stem immediately below the flower being flattened.

More recently a walk in Daventry Country Park produced another example, this time involving Black Bryony, Tamus communis. The stems of this climbing plant (which, incidentally is the only British representative of the Yam Family, Dioscoriaceae) were distinctly flattened, although the plant itself appeared healthy.



Black Bryony with the stem displaying fasciation. Daventry Country Park.

19 September, 2017



In Stefen Hill Pocket Park today a dandelion was also displaying fasciation and again it was the stems affected. They were greatly flattened, looking very broad from one direction...

The stem of this dandelion is very flattened. Stefen Hill Pocket Park.

20 May, 2019

...but extremely thin from another angle. The flower head was also distorted , though less obviously.



From this angle the degree of flattening is obvious.



Fasciation is always a malformation affecting the stem. No other organs are directly affected but, as in the case of the inflorescence of the Gaillardia there may be some consequent distortion.