Question

Similarity between mistletoe and cascuta

Answer 1

both are Parasitic plants that is the relation

Answer 2

Mistletoe is the most common name for most obligate hemiparasitic plants in the order Santalales. It is attached to its host tree or shrub by a structure called the haustorium, through which they absorb water and nutrients from the host plant. 

whereas

Cuscuta also called dodder is the name of a group of plants in the morning glory family, of which the species Cuscuta epithymum is most commonly used in healing. ... Cuscuta is a parasitic plant. ... Instead, it grows on other plants, using their nutrients for its growth and weakening the host plant.