Easy Draw Cactus. Draw half of a long oval at the top. Draw a tube for the cactus plant.
Draw two small stems. Draw a tube for the cactus plant. Draw the main cactus trunk.
Draw lots of rib lines on the left arm.
Draw rib lines in the center. Draw thorns on cactus. Using smooth lines carefully create the outlines of the cactus as in my example. 7 How to Draw a Cactus.