An endangered study model: Arnica montana
Arnica montana (common name wolf's bane or mountain arnica) is a long-lived, perennial herbaceous species most commonly found in grazed meadows, nutrient-poor moors, heaths but also coniferous forests.
It is easily recognizable by its big yellow flowers, typical fragrant smell and hairy opposite leaves organized in a basal rosette with ovate leaves and 2 upper spear-shaped, small leaves.
Achenes are wind-dispersed through a white pappus, despite dispersion appear to be limited to few meters. Arnica montana reproduces also via vegetative multiplication (through rhizomes) and individuals in the same cluster of rosettes are often found to be identical clones.
Once very common throughout Europe, it is now declining in most of its distribution range, with some exceptions at higher altitudes/lower latitudes, where still seems thriving (e.g. Romanian Carpathians).
This species predilects nutrient-poor soils, with moderate levels of grazing. This feature in particular, could be one of the main drivers of its decline given the widespread phenomenon of nitrification and the abandonment of grasslands toward more intensive agricultural activities. Furthermore, due to a self-incompatibility system (SI) small populations often exhibit low reproductive success due to reduced seed set and reduced fitness of the offspring.
Linneaus writing about Arnica..
Evidence of the fast decline of this flower can be found tracing back the words of Linneaus, who wrote in 1729 about Arnica montana < [...] växte på alla ängar och backar i Småland/[...] grow on all meadows and small hills in Småland>.
In the same area, at the present time Arnica is fastly declining (category VU in Sweden).
Over 150 biologically active substances have been isolated and identified from A. montana. The most important for their therapeutic uses are sesquiterpene lactones, flavonoids, phenolic acids (e.g. caffeic acid) and essential oils (e.g. thymol derivatives). Other constituents of A. montana are carotenoids, diterpenes, arnidiol, pyrrolizidine alkaloids, polyacetylenes, coumarins, lignans, and oligosaccharides. (X) Because of the relatively high content in sesquiterpene lactones (mainly helenalin), Arnica montana is well known for its medical uses against bruises and swelling, a feature that represents an additional source of threat as it is widely collected (sometimes illegally) because of its high economical and traditional value.
Arguably enough reasons to make efforts for preserving this incredible species.
A living chemistry lab
...a perfect study system
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perennial
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long-lived
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limited dispersion ability
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common vegetative reproduction
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endangered
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SI complex
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rich in secondary metabolites
All these features make this species a perfect study system for testing our hypothesis.