Mistletoe white berries that it bears in clusters of two to six. The Eastern mistletoe of North America is similar, but has shorter, broader leaves and longer clusters of 10 or more berries. The word 'mistletoe' derives from the older form 'mistle' adding the Old English word "tān" (twig). 'Mistle' is common Germanic (Old High German "mistil", Middle High German "mistel", Old English "mistel", Old Norse "mistil"). Further etymology is uncertain, but may be related to the Germanic base for 'mash'. Parasitism has evolved at least 12 times among the vascular plants . Molecular data show the mistletoe habit has evolved
Herbivore adaptations to plant defense saliva for the caterpillar "Helicoverpa zea", counteracts the production of induced defenses in tobacco. Similarly, aphid saliva reduces its host's induced response by forming a barrier between the aphid's stylet and the plant cells. Herbivores can avoid plant defenses by eating plants selectively in space and time. For the winter moth, feeding on oak leaves early in the season maximized the amount of protein and nutrients available to the moth, while minimizing the amount of tannins produced by the tree. Herbivores can also spatially avoid plant defenses. The piercing mouthparts of species in "Hemiptera" allow them to feed around areas