Hypericum linarifolium . Flax-leaved St.John's Wort

Flax-leaved St. John's Wort in Northern Portugal

9th June 2017

While on a walking holiday a brief rest stop allowed enough time to photograph a St John's Wort that did not did not look familiar. Only when looking through the photos on returning to Cambridge that I realised that I had been looking at a species I had never heard of, but one that does occur in the UK.

  The flower was typical St John's Wort and I was thinking Perforate St John's Wort as the petals had the black glands and the anthers were yellow, but the stem was round without the two ridges and the leaves were very thin. Something odd about this plant so I took some more photos.

It is always good to get a photo of the underside of a flower and this photos shows the sepals are less than half the length of the petals. The sepals have black glands on short stalks and black lines along the veins. The petals have black glands and red lines on the back. The stem is hairless and the narrow leaves are opposite on the stem and have the black glands but no translucent dots.

The leaves on the very upright stem were very narrow, almost like the Irish St John's Wort seen in Glengarriff , West Cork, but they only have three veins which run parallel up the leave and these have a more normal vein pattern.

Final shot of flower shows the five petals and the stamens , over 30 with yellow anthers. You can just make out the two of the three divergent styles with the red tips almost horizontally sticking out each side.

Hypericum linarifolium (  Flax-leved St John's Wort ) has a distribution from the North of Portugal , north through Spain and the western edge of France , especially Brittany and runs out with populations on the Channel Islands and just a few places in England and Wales as its most northern limit. Its stronghold in England is South Devon with a few outposts in Cornwall and Wales. It is also found on Maderia.

A full description of Hypericum linarifolium was found on line in the Journal of Ecology 1963 by R.B. IVIMEY-COOK.

This plant was found on 1st June on the granite hills near Chorense, Northern Portugal, on the old Roman Road.  Thanks to On-Foot Holidays for suggesting the route.
Trailing St John's Wort was also present on this Road.


Peter Leonard  9th June 2017

Pale Dog Violet at Lough Allua, West Cork.

Pale Dog Violet ( Viola lactea) is a rare violet in County Cork and Lough Allua is its only inland site, with some costal records from the Mizen and Sheeps Head peninsulas (ref BSBI maps).

On this years visit on 10th May only one plant was found but non flowering plants would have been easy to miss and  V lactea tends to flower later than other violets into June.

Almost pure white flower with a hint of violet, upper petals tend to be quite thin 2-3 times as long as wide. A feature which is mentioned in the new BSBI Viola Handbook is the lower petal has slight point to it (apiculate tip)  and this is clearly shown in this photo. I have not seen that in feature in other species and this a new feature to look for. The veins on the lower petal have clear purple veins with quite a lot of branching and no blurring. They are also quite long reaching about 75% down the petal before fading out.
All this looks good for a pure 100% Pale Dog Violet.

Side view of same flower showing pale yellow green spur, notched and quite short in length. Sepal appendages are just longer than stem thickness , estimate about 1.2 mm so are not as large as in Heath Dog Violet.  Sepals are pointed as in all Dog Violets.  Again all looks good.

Photo of whole plant showing leaves with tapered base ( cunate base) and apiculate tip ( broad point at tip). Leaf texture is thick and some slight purple veins showing but not as prominent as on some plants. The purple veins can also occur in Common Dog Violet.

Final shot shows habitat. Pale Dog Violet grows in gaps in the longer vegetation between the wet waterlogged shallow lake and the Gorse covered bank. This area is not the edge of main Lough Allua but a backwater.
A hundred meters south on the main Lough the violets are a different story, with Heath Dog Violets on the shore and Common Dog Violets on the dryer ground plus complications with hybrids.

Peter Leonard
16th May 2017

Heath Dog Violet ( Viola canina) Norfolk

Heath Dog Violet ( V. canina)  The search continues.

Armed with the new BSBI Viola Book (recently published ) I though it was time to find some pure 100% Heath Dog Violets.  I had noticed that the BSBI map was showing a few dots on the Norfolk coast in an area where I have been birdwatching in the past. The sand dunes just west of Holkham Pines is a great place  and good for a walk. Late April is a bit early for Heath Dog Violets but on arrival on 23rd April there were several hundred plants scattered over the dunes.  Not having seen violets in a dune habitat I was surprised how small the plants were, tiny leaves but almost normal size flowers.

23rd April 2017, North Norfolk Coast TF856458.  Side view showing the pointed sepals having large sepal appendages, short pale yellow spur and small leaves.

23rd April 2017.  Lower petal showing thin but very clearly defined veins. In full thickness they only continue about half way down the petal but they do continue very faintly almost to the end. No darker terminal band to the white throat. Pale yellow spur just showing and tiny leaves.

Habitat photo. Soil almost pure sand. No competition from grass yet.

This next shot shows the leaf. The largest leaf seen was only 12mm long and 7mm wide, many much smaller. Shape not typical in that only a few were seen with cordate ( heart -shaped) bases or the squared off base of more triangle shaped leaves. No basal rosette  of leaves present which was easy to see on plants growing in pure sand without any other plants around them. Thick with shallow crenate edges.    I was happy these were 100% V. Canina as all the plants looked the same without any variation.  There again nothing is 100% in Violets.

Final photo shows stipules with mainly forward pointing teeth (fimbriae) which are quite thick. In comparison a Common Dog Violet has stipules which have thinner fimbriae more hair like than tooth shaped and tend to stick out at right angles to the stipule (although some do point forward).
Leaf base on right showing slightly cordate (heart shaped) base. Due to the very small size of all the leaves at this site none seemed to have the triangular  shape often seen with Heath Dog Violet growing on better ground.

Peter Leonard.  26 April 2017

Heath Dog Violet and hybrids in New Forrest

Heath Dog Violet ( Viola canina) and hybrid with Pale Dog Violet.  New Forest. May 2015
The new Viola BSBI Handbook has been published and gives a good baseline for all the species and hybrids that occur in Britain and Ireland. It has the advantage of comparing the hybrids against the  parent species in table form, which the detailed coverage in the 'Hybrid Flora of the British Isles ' does not do, as it only covers hybrids.  Written by the same Mr Porter and Mr Foley the combination of both books gives much useful information and the key warning that violets have weak barriers to hybridisation.  It would now appear that a small percentage of hybrids are fertile and 'introgression may occur more widely than has been previously thought".

My previous attempts to find Heath Dog Violet have been searching Newmarket Heath in Cambridgeshire, where they are effectively gone and at Lough Allua in West Cork where hybrids with Pale Dog Violet ( V. lacteal) and Common Dog Violet ( V. riviniana) make finding a 'pure' example hard but not impossible.
An attempt to find Heath Dog Violet in the New Forrest started well but walking down the track I found paler and paler flowers which raised the possibility that  I was looking at hybrids with Pale Dog Violet.

Side view .
21st May 2015,  New Forrest.  Very large sepal appendages seem a consistent feature along with the pale greenish yellow spur colour. Looks good for Heath Dog Violet ( V. canina).

Front view ,
showing very thin veins on the lower petal which extend well down the length and no sign of the darker band at the edge of the white throat that V. riviniana often has.

Third photos a little further down the track shows a paler flower but flowers of intermediate colour were present. This photo was the palest found. It was going so well but.....

Final New Forrest shot from 21st May 15 shows pale flower and leaf shape tending towards Pale Dog Violet.  Concluded better retreat and look for pure Heath Dog Violet somewhere else. With more time it would have been interesting to check out these intermediate coloured plants to determine if they are hybrids and also if Pale Dog Violet were present. They were not showing any vigorous tendency which is often looked for in the hybrid.  

Peter Leonard.   24th April 2017

Smooth Catsear (Hypochaeris glabra)

Sunday 17th July 2016.
Right place, right time but a day late for the Cambridge Flora Group walk across Chippenham Fen: I decided on a backup plan to try and visit Cavenham Heath in Suffolk and look for Smooth Catsear.
 I had visited the heath many years ago and remember it as a sandy open area that might be suitable.
Smooth Catsear is very rare in Cambridgeshire and occurs more frequently in Breckland, across into Suffolk.
Right beside the track that runs across the Heath as it approaches Temple Bridge I found about a hundred plants which had mainly finished flowering but were showing off their seed heads.

The strange feature about the seeds is that some are beaked ( they become thin towards the pappus, the thin parachute of hairs than catch the wind to disperse the seed)) while others are not beaked, being thick right up to the pappus. In the photo above most are beaked but the outer ones are non beaked , all on the same flower head. This is a  special feature of Smooth Catsear and got me searching for an open flower to photograph.  Not far along the track I found a few plants which still had flowers, but none were open. Flowers tend only to open in the mornings.

The narrow shape is quite distinctive but the red fringing to the bracts is not a feature I have seen on any other composite ( Catsear, hawk bit, hawksbeard etc).

Final photo of reddish leaves, another feature.
A new species is always good, especially when you are searching for it.
Peter Leonard. Feb 2018

Dog Violets, an ID Nightmare?

 

Dog Violets are well known to be a difficult group due to variation and hybridisation. Classic ID features as described are often hedged with words like most, often, not always, sometimes....

A few photographs mainly of flower front views to illustrate the difficulties. Species covered are:-
Common Dog Violet ( V. riviniana)
Early Dog Violet ( V. reichenbachiana)
Heath Dog Violet ( V. canina)

Common Dog Violet ( V. riviniana) A classic example with typically wide upper petals. Photographed  in Hardwick  Wood, Cambs on 2nd May 2016. The veins on the lower petal are clear right to their tips and extend about half way down the petal. The white throat has the slightly darker purple band at its edge.

The wide upper petals can often be used to separate Common from Early DogViolet which typically has 'Rabbit Ears' that is narrow upper petals.




Next an example of a Common Dog Violet with atypical narrow upper petals.

This example has very narrow upper petals but you can just see the white spur which is a good indicator for Common Dog Violet in comparison to Early Dog Violet. These narrow flowered versions can make up to 10% of a Common Dog Violet population. The veins are not quite as clear as in the first example, not as clearly forked or as many but still more typical of Common than Early Dog. The white throat has the typical darker band at termination.  This photo was on 18th May 2016 at Gamlingay Great Heath. No Early Dog Violets were found at this location, so the possibility of this feature being an example of a hybrid was discounted but Botanists seem to fall into two camps, Broad Species converts believe hybrids are very rare while others believe hybrids are common. In practice the distinction between species variation and hybridisation is very difficult. A small percentage of hybrids are fertile and back cross to parents to give intermediate features (Ref Hybrid Flora of the British Isles).
Are these narrow petal versions in fact hybrids?
(Update:- Recent research from Europe shows hybrids between Common and Early Dog Violets do not occur, except very rarely. A separate blog covers this see Violets label section) In Britain it is probably very rare and over recorded. Hybrids occur with other species of Dog violets like Heath Dog Violet.)

If all narrow upper petal variants  consistently had other features which were towards the Early Dog Violet set, this might be believable but the example below shows a flower with quite narrow flowers but classic veins consistent with Common Dog Violet. Taken 5th May 2013, Oxwich Wood, Gower.

The photo right  has been selected as the veins are very long reaching beyond  75% of petal length. It is another Common Dog Violet photographed on 5th May 2013 , Gower, South Wales. The flower has the wide upper petals and a really strong clear and forked vein pattern. This flower has quite small sepal appendages , about 1mm in length (slightly less than the stem thickness) and a almost white spur tinged with the slightest hint of purple.









Next photo is Early Dog Violet ( V. reichenbachiana) which can often grow alongside Common Dog Violet, as in Hardwick Wood where this photo was taken. To date, all violets found at this site have been a distinct species and without any obvious hybrids but I will look again next season.

The dark purple spur can be seen behind the upper petals as the first indication that this is a Early Dog Violet ( however some Common Dog Violet can also have dark purple spurs which is not often mentioned in the field guides). There are only five veins and the tips are not clearly defined tending to blur out in the dark purple terminal band. This is typical of most Early Dog Violets. The upper petals are quite narrow but many have even narrower petals.

Second photo of a Early Dog Violet was taken in Eversden Wood, Cambs on 31st May 2014.   I have added a side view showing the long dark spur, pointed sepals and sepal appendages ( very small upper three, lower much longer showing another variable feature. Sepal appendages can be useful as an ID feature when large or small compared to stem thickness. They are often in between at about same as stem thickness ( 1-1.5mm ) so there is overlap in this ID feature.

This flower has classic Early Dog Violet bold veins, thick not forking very much and a bit blurred at the tips where they just go beyond the white throat. This flower does not have the terminal darker band at the junction of the white throat and the purple of the outer petal. This flower also has the narrow upper petals     'Rabbit ears' look.











The third photo of a Early Dog Violet was selected as it has veins which are forked and unusually are quite clear but still blurred at their tips. The number is still limited to three main veins and a couple of outer faint ones. Still more typical of Early than Common but only just.



The veins are quite short extending only a third of petal length. This and the limited number of major veins plus the lack of forking does seem to be a consistent difference between the species.  You can just see the dark purple spur behind the upper petals in this photo. The number of veins is yet another variable, Early Dog Violet generally has less but I suspect if you look at enough, some will not conform to a simple number count method of separation.






Next stage is to go back and look at Common Dog Violet in Ireland and consider the even more difficult Heath Dog Violet. The photo to the left has a pure white spur, quite wide petals and very clear veins that are well forked and extend beyond the purple band terminating the white throat.  This photo was taken at Lough Allua in County Cork, Ireland on 15th May 2015. It was considered to be a Common Dog Violet.

Very similar to the previous photo except veins are much longer, going approximately two thirds down the lower petal. A feature not outside the range of Common Dog Violet. There is no throat terminal purple band present. This photo was taken on 15th May 2015 on the South shore of Lough Allua in Co. Cork. It was regarded as a candidate for Heath Dog Violet ( V. canina) although Lough Allua is well known for hybrids between Common Dog, Heath Dog and the rare Pale Dog Violet.

With any Violet ID, all features of the plant have to be taken into account from leaf shape, extent of hairs on leaf, sepal appendages, shape of the side teeth on stipules and structure. In this case leaf shape is much longer than wide and some but not all leaves did have the squared off base ( not heart shaped) . The side view shows a short spur, white with a slight yellow green tinge plus very large sepal appendages.





The main problem with Heath Dog Violet is finding one in the first place. For example in Cambridgeshire it has not been seen at its last stronghold of Newmarket Heath for several years. It is now effectively no longer present and declining rapidly in many places.  Lough Allua has its problems with Hybrids so a trip to the New Forrest was undertaken.



The next photo was taken on 23rd May 2015 in the New Forest and was considered to fit with Heath Dog Violet  with long leaf shape and stipules with forward pointing teeth. The flower shows very thin veins with limited forking in this case. No dark purple band at the edge of the white throat. This ID was going well until we found more plants with quite pale flowers and this raises the question of hybrids with Pale Dog Violet ( V. lactea).  Heath Dog Violet is often stated to have very blue flowers but in Cork some Common Dog Violets  also have blue flowers. In Europe it can have a real spread in flower colour (rarely white through to purple) plus it has two sub-species ssp. canine and sap.montana.


The final photo is a Pale Dog Violet ( V. lactea) taken on 16th May 2015 at Lough Allua, Cork.

I am looking forward to the BSBI handbook on Violets due out in early 2017 as I am sure it will be a great help with this difficult group.  In addition the recent 'Hybrid Flora of the British Isles' covers hybrids and adds information from Europe which can be very different from Britain.



Peter Leonard, Rampton, Cambridgeshire
December 2016

Heath Dog Violet at Lough Allua, West Cork.

Heath Dog Violet (Viola canina)

15th May 2015

South Shore, Lough Allua, West Cork, Ireland

Despite many hours searching Newmarket Heath I failed to find any Heath Dog Violets. They have decreased in numbers to the point where they are  gone from Cambridgeshire. Newmarket Heath was the last stronghold with many plants present twenty years ago but more recently just a few plants have been found on occasional years.

Not only rare, they are also quite hard to distinguish from the Common Dog Violet. 

This is complicated by two sub-species which give Heath Dog Violet varied features plus the ever present complications of hybrids with both Common (Viola riviniana) and Pale Dog Violet ( Viola lactea) .

Given the difficulty and variation this small group on the South Shore seems to fit with Heath Dog Violet. They were growing in the short grass about a meter in from the waters edge. Sepal appendages were large, even larger than Common Dog Violet and the spur colour was pale yellow-greenish without any violet tinge. Common Dog can have completely white spurs but the greenish tinge looks good for Heath.
Leaf shape also looked good with leaf base more squared off with less of the heart shaped base that Common Dog Violet would normally have.