carnivore carnivorous Drosera glands leaf leaves plant rosette small sticky sundew sundews tiny bog droplet insectivorous marsh norway alien background eerie foliage odd strange texture unusual botanic garden botanics catch danger devour digests Dionaea muscipula eating flies flower flowers fly Flytrap glasgow green grip insect insect eating nutrition plants red savage trap Venus attract-prey attracted attraction carnivorous-plants clumps clusters coloring colors colouring colours cover digest digested digesting display distinctive edge edges enzymes flora funnel herbaceous insect-trap insects nectar-like-secretions nutrient-source nutrients operculum passive-trap perennials pitcher-plants pitchers pitfall-traps prey proteases rims slippery species variations variety vegetation veins