Tadasana, Samasthiti, or Palm tree pose is an asana. Depending on the Yoga lineage practiced, Samasthitiḥ and Tāḍāsana may refer to the same asana or another similar asana.

Strengthens: Knee, Thigh, Ankle
Preparatory poses: Uttanasana, Adho mukha śvānāsana
Pose type: Standing
Also known as: Mountain pose, Samasthiti
Base Asana: Tāḍāsana is itself a fundamental āsana

Stand with the feet together. Extend your toes; don’t grip the floor or mat. Balance evenly on the front and the back and the sides of the feet. Be active in the thighs to lift the knees. Do not push the knees back. Rotate the pelvis back to take tailbone toward the floor. Feel the spine lengthen out of the sacrum, stretching each vertebra away from the vertebra below it. Lift the sternum. The shoulders stay relaxed and down. Rotate the upper arms outward. The palms of the hands face the thighs. As the neck stretches upward, keep the neck, throat, and jaw relaxed. The chin is parallel to the floor. Visualize a straight line running from your chin, to your sternum, to your pubic bone. Soften your gaze; quiet your hearing; relax your jaw. Breathe evenly and comfortably through your nose.