The Lotus posture can take years of training to perfect and should not be attempted by novices. The lotus is so-called because the position of the legs resembles a blooming lotus flower.
The lotus stimulates the spine, bladder, abdomen and pelvis. It also has a calming effect on the nervous system although it also places a lot of stress on the joints of the knee and hip.
You should not attempt the lotus posture if you are suffering from injured knee, ankle or hip joints, if you suffer from sciatica.