Crepis mollis ( Northern Hawksbeard ) and adjacent Hawkweeds.
Notes and photos from Mid July 2019. A visit to Allendale, Northumberland.
|Crepis mollis with phyllaries highlighted.|
As mentioned in my previous blog on Smooth, Rough and Beaked Hawksbeards, there is a really excellent article on the identification of Marsh, Northern and associated Hawkweeds on the Cumbria Botany blog written by 'JR'. This article also covers the potential confusion with the Hieracium vulgatum, a Hawkweed that often grows with Northern Hawksbeard. Without this article written by Jeremy Roberts and supported with photos by Phil Brown, I think I might have struggled. Both these botanists are BSBI recorders for Cumberland with years of experience, so it is interesting to see what they found as good ID features and what they left out. REF http://www.cumbriabotany.co.uk
The second advantage was that I had found several articles on the occurrence of Northern Hawksbeard, written in the South Northumberland Newsletter by BSBI recorder for vc67, John Richards. An e-mail requesting good locations to John Richards, provided two sites and this was much appreciated. I was also lucky in that 2019 was a good year for Northern Hawksbeard. See article :-http://www.botanicalkeys.co.uk/northumbria/67Newsletter27SEP2019.pdf
So with a good ID article and good site locations I headed north to see and photograph two new species. This blog covers Northern Hawksbeard and the nearby Hawkweed which could be confusing unless you really look at the differences in detail.
The Cumbria Botany article picks out leaf shape as a key difference to separate C. mollis from Hieracium and also secondary features like colour of the pappus and achene shape.
It is interesting they don't really look at the involucral bracts (phyllaries), which are supposed to be the best differentiator between Crepis and Hieracium , ref Sell Vol 4 Page 202. Crepis are supposed to have a long and a short row of involucral bracts ( phyllaries) which form a cup and saucer. The key here, is two distinct rows. The species Smooth, Rough and Beaked, as covered in my previous blog, all show this feature well but I found that Marsh and Northern are not very good at following this rule.
Possibly this is due to both Marsh and Northern being sectioned off into different grouping by Sell, outside the section 'Crepis' that includes Rough, Smooth and Beaked etc. Although all have a scientific name starting with 'Crepis' apparently large groups, like Crepis (which has 200 species worldwide) are often split into sub-groups.
Stace is using the term 'phyllaries' instead of 'involucral bracts' so from now, I am changing over to this term as it is more precise, rather than use just the word 'bracts'.
|Crepis paludosa with phyllaries highlighted.|
|Crepis mollis with phyllaries highlighted.|
|Hawkweed at Allendale Town|
The main point is that the crepis species here,
does not clearly have two rows of phyllaries, with the outer row being adpressed and of different lengths.
As a main differentiator, this feature is a failure as far as I am concerned. See highlighted phyllaries in photos.
Both Crepis paludosa and Crepis mollis have phyllaries with prominent dark hairs with glandular tips. The hawkweed phyllaries do not have obvious glandular hairs however if you look very closely, a few can be found. Marsh Hawksbeard sometimes can lack the glandular tips on these hairs so it's not an absolute ID feature. The Northern Hawksbeard according to Sell, always has glandular hairs on the phyllaries.
The dark hairs on the Marsh Hawksbeard (C. paludosa) are very long and definitely look for dangerous from an insect's point of view!.
My first Northern Hawksbeard.
|C. mollis near Allendale Town. 17th July 2019|
|C. mollis lower leaf, not the best example of impressed veining.|
|C. mollis lowerl leaf underside paler and hairy.|
The lower basal leaf shape is elliptical with a blunt end, entire in that it has no protrusions or lobes on the margin unlike the hieracium which has toothed edges. This particular leaf above is not showing the impressed vein pattern that the Cumbria blog suggest is a typical feature, but this could be down to variation and lighting conditions. The next photo below shows this feature a bit better.
|C. mollis, lower leaf showing leaf surface impressed veining.|
|Hieracium basal leaf|
Main difference is the toothed margin and the way the leaf does not taper down to a winged petiole.
The teeth may be more or less developed.
|Hieracium lower leaf underside, paler and hairy.|
While on the subject of leaves , next up are mid stem leaves.
|C. Mollis, mid stem leaf.|
|C. mollis, mid stem leaf with Semi-amplexicaul base|
Note the tiny red protrusions which are hydathodes which are spaced along the leaf margin and can give a slight toothed edge to the margin but not to the extent of the Hieracium toothed edges.
|Hieracium mid-stem leaf, toothed margin prominent.|
|Hieracium Upper leaf showing no clasping to the stem.|
|Hieracium mid stem leaf showing semi-amplexicaul clasping of the stem.|
In conclusion, the C. mollis have leaves that are without the teeth of the Hieracium, have a narrowly-winged petiole on the basal leaves and can have impressed veining.
3) Pappus and achenes.
Next feature mentioned in the Cumbria blog is that C. mollis has very pure white pappus hairs.
|C. mollis pappus hairs bright white.|
|Hieracium at Allendale Town.|
|C.mollis showing pure shinning white pappus hairs.|
|C. mollis achenes,|
No sign of beaking and with tiny ribbing. I can just about count 8 on the visible side so at least 16 ribs.
|Hieracium achenes, dark brown and pappus hairs not pure white.|
These Hieracium achenes are typical of all the Hieracium I have ever seen, not that I am very familiar with this complex group. Typically they are very dark and only slightly curved. Main feature is that the abrupt pappus end is not tapered at all. The ribbing is uneven and I counted ten ribs only.
Conclusion. The Cumbria blog is very keen on the achene difference as being totally distinctive in terms of achene shape . Interestingly they show Hieracium achenes that are brown in colour, so achene colour may not be as useful as I thought, having believed all Hieracium had almost black achenes. With achene shape and the leaf shape conforming to the Cumbria blog, I left happy that I had seen Northern Hawksbeard plus an interesting but similar Hawkweed.
|C. mollis, showing two pronged stigma and styles are not pure yellow- more greenish.|
|C. mollis showing the stigma but very little of the style as it's enclosed in the stamen/anther.|
|C. mollis, phyllaries with glandular hairs.|
|Hieracium Flower showing stigma slightly darker than petals.|
|Hieracium from Sinderhope site, with anther structure yellow and slightly darker stigma.|
|Hieracium from Sinderhope site.|
The hawkweeds seen all had two or three stem leaves. Leaves had thin simple hairs on the margins and lower surface, a few simple hairs on the upper surface. I did not see any stellate hairs on the leaves.
|Detail of hairs on phyllaries showing long black (but white tipped) non glandular hairs plus a few short glandular hairs.|
|Shining white pappus hairs|
on C. Mollis
|Off white pappus hairs on Hawkweed|
24th January 2020
Peter G Leonard.