Cactaceae cactus Echinocactus grusoni Golden Ball Golden Barrel Cactus Mother-in-Law's Cush thorns yellow barb barbs botanic garden desert plant echinocactus gardening glasgow grow growing grusonii nature old plants stings thorn barrel Cacti danger defence defense ornamental plant pointed Prickly sharp spines spiny xerophyte arid barrel cactus clumps clusters coloring colors colouring colours compact covered globose globular perennial points pronounced ribs protective pups ribs round shape shaped skin soft-wooded perennial spikes spination surface symmetrical symmetry thick tough skin to-the-point appearances barrel-cactus display edge edges flora garden-display garden-plants green irregular leaves light perennials protection ribbed ribbing shapes short-spikes small-spines succulents sunlight surfaces textures unusual Arizona cacto desert kaktus organic rib southwest spine texture vegetation western frilled frills tall variety