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Project Noah Nature School
Parnassia palustris
This is a very rare flower that grows in the dunes of Ter Yde. They have protected areas where marshes can grow in the dunes and this is where the Parnassus are. Parnassus belong to the family Saxifragaceae. Each plant grows a single white, showy flower which stands atop an upright, slender, bald stem. The attractive flower consists of 5 conspicuously-veined petals that are 8 to 13 mm in length. the leaves are produced in a rosette at the base of the plant, except for a single leaf on the middle of the flowering stem. The leaves are heart-shaped and taper to the base. The numerous, tiny, oblong seeds are encased in an oval-shaped, four-valved fruit capsule. The flowering takes place between July until September. The flowers are hermaphroditic. In hermaphroditic flowers, both male and female organs may block each other's access to pollinators, thus leading to anther-stigma interference. P. palustris solves this problem by means of stamen sequential movement. How does this happen? The flower has five sterile stamens between the fertile stamens and the petals These are called staminodes and have become lobed, and the tip of every lobe has a drop-like, honey-coloured bud. The small flies and hymenopterans that pollinate the plant are attracted by the nectar and the nectariferous base. The fertile stamens ripen and dehisce successively curving towards the petals and away from the centre of the flower. Only one of the five in the flower is active at any one time, prolonging the male phase of the flower and exposure of the pollen to pollinators. The stigma opens up to receive pollen only when all the stamens are empty, in this female phase it receives pollen brought by the pollinators. These mechanisms altogether, optimize and promote a longer period of cross-pollination. You can find more on this cool mechanism of pollination in these references: https://www.ncbi.nlm.nih.gov/pmc/article... http://journals.plos.org/plosone/article...
Ter Yde dunes, Belgium. http://www.natuuralsgoedebuur.be/~/media...
Spotted on Jul 31, 2016
Submitted on Aug 6, 2017
7 Comments
Not in Scotland, where I was and at the time I visited but I am sure there are places where they can be found as well. I learned of this colony of Parnassius via one of the naturalist associations here in Flanders. They are protected so that you cannot enter where they are, but luckily there are some also growing out of the fenced areas. I was very happy to find them, as you can imagine :-)
Thank you Marta! It is also interesting to find out they grow in these dunes and are protected there. Did you spot any in Scotland when you visited there?
It piqued my interest too and I have just read that these flowers are hermaphrodite and can be pollinated via insects but also they can pollinate themselves. One cool feature is sequential stamen movements: anthers present pollen one by one at the flower center on different days and then bent away and down to overlie the petals before the stigma is exposed. I will add to the spotting a reference to an article explaining this mechanism in more detail.
Thanks Daniele :) Nature is amazing!
staccyh, I attempted to summarize it here in simple terms:
http://www.projectnoah.org/spottings/964...
Here's a reference:
https://www.ncbi.nlm.nih.gov/pmc/article...
Lovely little flower. How are they pollinated Daniele? You've piqued my interest!
My favorite flower :-) They are pollinated in the most extraordinary way.