Anagyris foetida (English common name stinking bean trefoil), is a species of flowering plant in the family Fabaceae, forming a malodorous, Summer-deciduous[1][2] shrub or small tree 2-4m in height with green twigs bearing grey-green trifoliate leaves clad beneath in silvery hairs.

[4][5] [6] The genus name Anagyris is a compound of the Ancient Greek prefix ανα (ana-) "up / back again / backwards" and γῦρος (gŷros), "ring" / "round", giving the meaning "bent back into a ring" - in reference to the curved pods of the plant, while the Latin specific name foetida is the feminine form of the adjective foetidus, meaning "stinking" or "smelly" - in reference to the foul stench of the bruised leaves, which is said to resemble that of spoiled beans.

by its unusually large and heavy seeds),[15] which suggests that its original homeland may have lain somewhere in the refugium encompassing the Balkans, Türkiye and the Black Sea coastal region of the Caucasus.

It grows in calcareous soils in seasonally arid areas exposed to the hottest summer sun, favouring rocky limestone escarpments (as currently at Mont Faron), often among the ruins of castles and abbeys (see also monastic garden), suggesting that it may be a relic of cultivation for medicinal purposes or even to furnish an arrow poison for military use.

[3] This was substantiated by Ortega-Olivencia et al. who carried out a study of the pollinators visiting two populations of the plant in Southwest Spain over a three-year period and recorded their findings in a paper of 2005.

[21] The authors offer the following plausible explanation for the unusual form of pollination which has evolved in the case of A. foetida: The negligible existence of insect visitors and pollinators of A. foetida flowers could be explained by the early flowering of this species during the autumn–winter, coinciding with the coolest and wettest months of the year (cold, high winds, almost daily mists that persist until nightfall, and above all, abundant rainfall).

The species found generally to operate as a nectar thief was the Palestine sunbird (in consequence of its longer bill), although even it could act as a pollinator, on occasion.

After the heat of summer and the arrival of autumnal rains, the papyraceous–coriaceous pericarp (papery, corky pod) begins to rot, passing from brown to blackish in colour, and leaving the seeds exposed.

The authors are cautious in applying conclusions drawn from data gathered solely in Spain, but nonetheless offer pointers for future research in other countries where the plant is native.

The large blue-black seeds of Anagyris foetida bear a strong resemblance (particularly when seen from a distance) to the fruits of Olea europaea var.

This is due principally to the shrubby habit of the plants and constant presence of sheep (always present during the period of ripening of the fruits, when predation has the most negative effect).

They speculate that, in habitats modified less by agriculture than those of the Spanish locales in which they carried out their research, other mammals, such as deer, foxes and hares might be involved (indeed, they do not even rule out sheep completely as vectors elsewhere in the plant's range).

If it still exists [italics added], this disperser is likely to be a mammal since the latency of the seeds of this species, which are hard and impermeable, is broken physically through biting and by the action of stomach acid.

Scarification of the seeds before their immersion (whether chemically by acids or mechanically by nicking, filing or similar damage from the teeth of sheep) on the other hand, could result in complete imbibition within 48 hours - this being indicated by colour change.

These anthocyanin pigments not only mimic the dark colours of black olives, but also confer resistance to pathogens, since they possess antibacterial properties providing a measure of protection of the seed coats from breakdown by soil bacteria.

[23]The first to write an account of the folk medicinal properties of A. foetida [24] was Ancient Greek herbalist and physician Pedanius Dioscorides in his monumental work De materia medica.

[3] The seeds of the plant were formerly employed as an emetic (which Renaissance doctor and botanist Matthiolus observed was so violent in its action that it could cause internal bleeding),[3] while an infusion of the leaves was used as a purgative, but neither use should be considered safe, given the extreme toxicity of the species.

[26][27] The alkaloid anagyrine, present in the seeds, causes, in warm-blooded animals, first slowing of the breathing and heartbeat and ultimately cessation of respiration and cardiac arrest.

That the plant was deemed proverbially smelly in Ancient Greece is demonstrated by a punning exchange near the beginning of the celebrated comedy of circa 411BCE Lysistrata, by the playwright Aristophanes:[24] [Several women enter, headed by MYRRHINA, from the deme (=suburb) of Anagyrous.

[32] The shrub of Anagyrous groweth near all the great roads of the isle, so stinking that it maketh the head to ache, and there doth keep its ancient name, for the common people do call it "Anagyros".

[33]Thus writes Pierre Belon (1517–1564), French diplomat, traveller, and pioneering naturalist, in an essay devoted to the notable plants of the area surrounding Mount Ida (now known as Psiloritis) on the island of Crete, which forms part of his Observations - a work devoted to the noteworthy things which he observed during his travels in Arabia, Greece and the countries of the Eastern Mediterranean.