The Lichen Collection

Lichens are unique composite organisms composed of two distinct components: algae and fungi, living together in a symbiotic relationship (symbiosis). This specialized partnership grants lichens the resilience to survive in diverse habitats, including some of the most extreme environments on Earth, such as the polar regions and arid deserts. The lichens in the Garden’s collection were gathered from various regions across Israel and are displayed growing on different types of stone substrate.

In the collection, one can observe the three primary growth forms of the thallus (the vegetative body of the lichen):

• Crustose Lichens: These have a crust-like thallus that adheres tightly to the rock surface, forming a dense, carpet-like layer.

• Foliose Lichens: These are characterized by small, leaf-like lobes that branch out over the stone. This thallus is attached to the substrate only at specific points.

• Fruticose Lichens: Representing the most complex growth form, these are attached to the stone at a single point and extend outward in a three-dimensional, shrub-like structure.

Nature’s Air Quality Monitors

Due to their ability to efficiently absorb substances directly from the atmosphere, lichens serve as excellent bioindicators (biological detectors) for air pollution. For this reason, the Lichen Collection was strategically positioned within the Botanic Garden overlooking the bustling Ayalon Highway, allowing researchers to monitor the environmental impact of one of Israel's busiest traffic arteries.