The relationships between bees and flowers are various, however the goal is the same, nutrition in return for pollination. Pollen and/or nectar is readily available in blossoms without perianthers (willow) and several blossoms with radial symmetry (gooseberry, apple, roses and many Compositae). In more complex radial symmetric blossoms (iris) and the majority of zygomorphic blossoms (clover, lupin, nettle, snapdragon, monkshood) demands are made on insects in terms of proboscis length, body weight, stamina and strength.