Druse_(botany)
A druse is a group of crystals of calcium oxalate,[1] silicates, or carbonates present in plants, and are thought to be a defense against herbivory due to their toxicity. Calcium oxalate (Ca(COO)2, CaOx) crystals are found in algae, angiosperms and gymnosperms in a total of more than 215 families. These plants accumulate oxalate in the range of 3–80% (w/w) of their dry weight[2][3] through a biomineralization process in a variety of shapes.[4] Araceae have numerous druses, multi-crystal druses and needle-shaped raphide crystals of CaOx present in the tissue.[5] Druses are also found in leaves and bud scales of Prunus, Rosa,[6] Allium, Vitis, Morus and Phaseolus.[7][8]