Rock beard (scientific name: Cassiope selaginoides Hook. f. et Thoms.), is an evergreen dwarf semi-shrub, 5-25 cm high; the branches are many and dense, rising outward or spread out into a cushion shape, densely opposite to each other Raw leaves. Leaves hard leathery, lanceolate to lanceolate-oblong. Flowers single axillary; calyx 5, green or purple, lobes ovate-lanceolate or lanceolate; corolla milky white, broadly campanulate. Capsule globose, style persistent. The flowering period is April-May, and the fruiting period is June-July.