Red lichen marks can be seen among many of the monuments at Persepolis. Lichen secretes organic acids, particularly oxalic acid, which can dissolve minerals. It has wormed its way into stone ...

However, take a closer look and you'll see some interesting differences. 'Lichens come in many colors (yellow, red, orange, blue and grey) and a few different shapes,' says horticulture expert ...

Much like “blood snow”—the red streaks found on some glaciers—the source is plant-based. The “blood rain” is actually a downpour of algae. It’s a type of lichen called Trentepohlia ...

Because of its potential association with systemic diseases and malignancies, it is recommended that patients with spiny ...