Anemone nemorosa, A. ranunculoides and their hybrid

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Rørslett, B. 2013. Anemone nemorosa, A. rancunculoides & their hybrid (Ranunculaceae). Wood and Yellow Anemone. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...d-their-hybrid/

 

Anemone nemorosa L.

NO: Hvitveis; kvitsymre

SE: Vittsippa

DK: Hvid Anemone

FI: Valkovuokko

DE: Busch-Windröschen

EN: Wood Anemone

 

Anemone ranunculoides L.

NO: Gulveis; gulsymre

SE: Gulsippa

DK: Gul Anemone

FI: Keltavuokko

DE:Gelbes Windröschen

EN: Yellow Anemone

 

These gregarious species carpet the floor of deciduous forests in mid to late spring by means of their creeping rhizomes. Both are widely distributed in Europe and adjacent parts of Asia. Towards the north, A. ranunculoides becomes the less frequent of them, but still extends north of the Polar Circle in Norway. They often grow intermingled or in close proximity, and as their flowering periods overlap, one would not be surprised by existence of hybrids. Yet intermediate plants are uncommon and mainly seen in ecologically unstable habitats such as along lake shores.

 

A. nemorosa has the largest flowers of the two. Its sepals are more narrow than those of A. ranunculoides, and tend to be present in a higher number (6-8 being typical). The flowers usually are white or cream white often with purplish markings by anthocyan substances. Sometimes flowers can be red all over. A. ranunculoides has broader and more obtuse sepals and they usually number five. Its flowers are a deep pure yellow.

 

The uncommon hybrid, A. nemorosa x ranunculoides, has strikingly pale yellow flowers which are intermediate in size between its parents. The sepal outline reminds of A. rancunculoides being broad and obtuse at the apex. The strong venation is a trait from A. nemorosa. The foliage is variable in appearance and tends often to be quite nemorosa-like. Flowering is erratic and some years the plants stay in a vegetative state, which of course makes the hybrid easy to overlook. I have never seen normal seedset or fertile fruits developed.

 

Plant material collected and photographed at Rotlia Nature Preserve, Hedmark, Norway, over several seasons (2010-2011). This location has a regular occurrence of A. nemorosa x ranunculoides, but as earlied noted, flowering is irregular over the years so several visits were required.

 

The two parents can occur literally entwined.

 

Image reference: ANEM_SPP_I1005211233_VIS.jpg

 

Their UV appearance is remarkably different. A. nemorosa shows patches of conical cells that are scattered on the sepals, so there is no clear-cut pattern in their occurrence. Individual flowers can range from almost free of such patches to being nearly completely covered by them.

 

Image reference: ANEM_SPP_I1105082777_UV.jpg

 

Another flower of A. nemorosa to show the variability of the presence of conical cells.

 

Image reference: ANEM_NEM_I110521011163_UV.jpg

 

Sepals of A. ranunculoides don't have obvious conical cells on their proximal side, but the distal (rear) side are UV black and may have conical cells present.

 

Image reference: ANEM_RAN_I1105082769_UV.jpg

 

The hybrid is immediately evident by the pale yellow flowers (coloured like powdered sulphur) and the strong patterns of veins on its sepals. The veins are not embedded as with A. ranunculoides. The sepal shape reminds of the latter species, though.

 

Image reference: ANEM_NEM_X_RAN_B1005080652_VIS.jpg

 

Seen in UV light, the flowers of A. nemorosa x ranunculoides have a mottled appearance with colour blotches of either parent. Veins are UV dark so make the venation even more prominent than in visible light.

 

Image reference: ANEM_NEM_X_RAN_I1105082761_UV.jpg

 

 

[Published 5 April 2013 Last update 10 July 2014]