Tuesday 28 April 2020

Rough Hawkbit vs Lesser Hawkbit Phyllaries.

Rough Hawkbit vs Lesser Hawkbit Phyllaries.
A few additional images to demonstrate the differences in the phyllaries (involucral bracts) of Rough and Lesser Hawkbit.
This photographs supplement my original blog Hawkbits (Leontodon) from 22Dec2017 which should be read first. There is also a blog 'Leontodon Achene Photos' 21Nov2018.

Rough Hawkbit ( Leontodon hispidus)
Lesser Hawkbit ( Leontodon saxatilis)

Rough Hawkbit
Lesser Hawkbit

Lesser Hawkbit
Rough Hawkbit




Rough Hawkbit



Many Lesser Hawkbit have a clear brown
edging to the inner phyllaries which can be quite distinctive.
Rough Hawkbit can also have brown edging but usually it merges into the green centre of the phyllaries without having a distinct edge.

Lesser Hawkbit often has no hairs but some have white hairs. In general Rough Hawkbit has  hairs on the phyllaries but occasionally some plants have none. Having no hairs becomes usual for Rough Hawbit in Eastern Europe, east of Vienna but here in the UK hairless Rough Hawkbit might indicate a hybrid.
The outer phyllaries tend to be longer in Rough Hawkbit with the very longest reaching 90% of the inner phyllaries whereas Lesser Hawkbit only reach 50%.

A few more examples for brown edged Lesser Hawkbit follow.


Lesser Hawkbit

Lesser Hawkbit



















Lesser Hawkbit



Lesser Hawkbit



















Rough Hawkbit
Lesser Hawkbit






















Rough Hawkbit
Lesser Hawkbit




















Two Classic examples follow.

Lesser Hawkbit , classic example with no hairs, distinct dark outer line to inner phyllaries and short
outer phyllaries.
Lesser Hawkbit but this time with hairs. Note the distinctive dark edging to the inner phyllaries
and the short length of the outer phyllaries.



Rough Hawkbit  showing lots of hairs and very long outer phyllaries.

Below are examples of possible hybrids based on these particular flowers being different from the surrounding population.
As R.A Finch concluded in his famous paper on Leontodons*, ' concealed gene flow occurs both ways between these two species' so hybrids are probably more common that we might think, even if we can't be certain of their identity as hybrids.  
Possible hybrid, no hairs, long outer
phyllaries and no distinct dark edge.
Possible Hybrid. Outer phyllaries not adpressed,
not very hairy but some dark edging.   





















Possible Hybrid, brown edging very faint.
Not very hairy.

Rough Hawkbit, Typical with brown edging merging
rather than forming a clear edge. Outer phyllaries
not adpressed. Moderately hairy .

























Peter Leonard
Rampton
Cambridge
29th April 2020

*ref . Finch, R. A.   (1967) Natural chromosome variation in Leontodon. Heredity 22;359-386