Friday, June 28, 2019

Rough Hawk's-beard (Crepis biennis)

Crepis biennis in summer breeze. Swindon, 28th June 2019.


Crepis biennis (En: Rough Hawk's-beard, Sw: Skånefibbla)

A new one on me, but probably I just haven't been paying attention. It's a sturdy biennial, much taller than the more common Beaked Hawksbeard (Crepis vesicaria) -- the three plants on my daily walk are all over a meter -- and flowering several weeks later. (It also lacks the latter's red colouring on the back of the florets.)

It's native on chalk in a rather restricted region of SE England (Kent, Surrey, Hertfordshire), but is also an increasing introduction elsewhere, generally in man-made environments. Hence its appearance here, in Swindon.

It's more frequent in the south, rare and casual by the time you get to Scotland. (In Sweden it's common only in Skåne, casual elsewhere. Common throughout most of mainland Europe.)


Crepis biennis. Swindon, 28th June 2019.

Crepis biennis. Swindon, 23rd June 2019. 

This one is getting on for 1.5m tall.

Crepis biennis. Swindon, 23rd June 2019.

The buds and involucres have a neat attractive appearance, with short patent hairs and phyllaries in two rows, the outer row somewhat spreading.

Clive Stace, for some doubtless very good reason, doesn't employ the term "involucre" in his New Flora of the British Isles, but I can't seem to lose the habit of using it as a collective term for the phyllaries (green bits!) that surround the capitulum (composite flower-head; the yellow part!).


Crepis biennis. Swindon, 23rd June 2019.


Leaves and stem of Crepis biennis. Swindon, 23rd June 2019.

The plant is not as rough as the name led me to expect, but there are patent hairs on at least the leaf-edges and the midribs (above and below), and on the ridges of the stem.


Flower of Crepis biennis. Swindon, 23rd June 2019.



Developing seed-heads of Crepis biennis. Swindon, 2nd July 2019.



Developing seed-heads of Crepis biennis. Swindon, 2nd July 2019.


Crepis biennis. Swindon, 30 July 2019.

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