Additional notes and photos on flowering Geraniums to support the ID Key features Blog.
The ID Key features blog, August 2019 is a reduced set of features to distinguish between all the wild Geraniums found in the UK when in flower.
Additional features and photos are included here to give a more complete picture of the differences.
Three species are covered in this blog which share a common feature in that they do not have extension tips to the sepals.
The leaves are cut to 2/3rd towards base and are of a similar shape.
Dovesfoot Cranesbill ( Geranium molle)
Small-flowered Cranesbill ( Geranium pusillum)
Hedgerow Cranesbill ( Geranium pyrenaicum )
1) Dovesfoot Cranesbill ( Geranium molle)
Petal colour is often the first clue in separating G. Molle from G. pusillum, normally being a deep pink, however white forms are common with intermediate colours also common, including some with a pale purple tinge.
Small-flowered, (G pusillum) often have a blue tinge in the petals which are also often narrow with a gap between them.
Small-flowered G. pusillum in all the photos I have taken, have had a pale off-white stigma whereas G. molle have had a pink or reddish purple stigma.
|Pale form but still has red/purple stigma.|
Occasionally the petals may not have the notch, see the comments and photo at the end of the ID Key August blog.
The style splits into 5 curved stigma arms at the centre of the flower, with the stamen filaments holding the anthers arranged round the stigma in two rows. G. Molle has ten anthers whereas G. pusillum has only five of its ten stamen filaments having anthers. Anthers do fall off (after splitting to reveal pollen) so this feature may not be a clear cut in some flowers.
|A pale pink version that is quite unusual. 24th June 2019, Cambridge.|
|Normal deep pink colour, Ten blue anthers present.|
|Ten anthers present , 5 have split and have revealed their pollen and the other 5 are held lower into the flower and line up with the petal centre lines. 22nd Sept 2019 Rampton.|
Hedgerow Cranesbill (G. pyrenaicum) has flowers twice the size of Dovesfoot Cranesbill (G.molle) and the sepals are shorter relative to the length of the petals. Size is always a dangerous parameter in plants as growing conditions can change some features more than others. Often flower size is largely maintained even when produced from tiny malnourished plants.
|Hedgerow Cranesbill (G. pyrenaicum ) with short hairs on sepals.|
|Side view showing tips of the sepals just short of the petal notches, approx 2/3rd of the lengths of the petals.|
|Side view, note long hairs plus short glandular hairs on sepals, a feature shared with G. pusillum.|
|Flower and leaf stems have 3 hair types, short glandular hairs, short simple hairs and very long hairs.|
|Mericarp at base of beak showing wrinkled groves and the impossibly small hairs which the photo does not show.|
The seeds are held inside the mericarp case. G. Molle.
|Comparison of mericarp at same stage showing the lack of groves and abundant hairs for Geranium pusillum.|
2) Small-flowered Cranesbill ( Geranium pusillum)
Small flowers and no long hairs on flower and leaf stalks, separate pusillum from molle. Leaf shape has been used in non flowering plants, as a identification feature but I found this too difficult. Much easier to use hair length.
The leaves are split to 2/3rds towards base and are very similar to G. molle. The flowers are small and the three veined petals have either no or very limited overlap. G Molle petals often overlap but there is variation with some having no overlap. The sepals have long hairs plus short glandular hairs much like G. molle.
|G. pusillum, white 5 pointed stigma with 5 anthers only as the other 5 stamen lack anthers. Hard to see in this photo.|
|Side view showing sepals nearly as long as petals. Long hairs on sepals.|
|G. Pusillum showing pale stigma and five anthers. 13th June 2019, Rampton|
|G. pusillum, leaf stalks which have no long hairs, just short hairs (glandular and non-glandular).|
|Section of flower stem and sepal at base of flower showing hairs.|
Flower stem hairs, a dense combination of straight simple hairs and glandular hairs , all short.
|Typical leaf from a small plant growing in a gravel drive.|
|More complex leaf of G. pusillum growing in good soil.|
|Hairy mericarps attached to the beak. G. pusillum, Rampton 24th Sept 2019|
3) Hedgerow Cranesbill ( Geranium pyrenacum)
|Geranium pyrenacum pale form|
|Side view of pale form of G. pyrenaicum|
|Normal pink flower showing the inner 5 anthers having split and the outer 5 still intact.|
Note the stigma has not opened.
The photo above shows the Hedgerow Cranesbill follows other larger cranesbills in that the stigma is not open to receive the pollen from the split anthers at least at first, suggesting pollination is dependent on insects rather than self-pollination that may occur in the smaller species like G. molle.
First 5 anthers have fallen off and the second set of 5 have split open. Stigma has also opened with its 5 pale pink arms. The Hedgerow Cranesbill seems to have a more complex timing arrangement of pollen and stigma availability, but from a identification view only, the stigma is pale pink and has thinner longer arms than G. molle.
|Short hairs, mainly glandular on flower stalks.|
|Leaf stalk has 3 types of hairs, with short glandular and non-glandular plus long simple hairs.|
|G. pyrenaicum . Leaf split into in this case 7 sections by cuts up to 2/3rds.|
Leaves can be split into from 5 to 9 lobes/sections depending on how deep the cuts go and this is open to different points of view, as you can't use the vein structure to give a clear result.
|Seeds just before they get thrown from the mericaps.|
As usual, I use the excellent 'Harrap's Wild Flowers' as my constant companion in the field.
Additional information on Geraniums was also found in 'Hardy Geraniums' by Peter F. Yeo which has detailed introductory chapters on the family. It covers both wild and cultivated types.
I am fortunate that both G. Molle and G. pusillum both grow in my gravel drive here in Rampton.
I suppose the good news is that to date, none of these three species has hybridised so identification should be straight forward. It is just a matter of remembering the key features which is why I made up the ID Key blog in the first place. Please comment if you see any incorrect assumptions.
24th September 2019