M D Hatch and C R Slack found that in certain plants growing in tropical climates, the first product of photosynthesis is a $C_{4}$-compound instead of a $C_{3}$-compound. These plants are now known as $C_{4} - \$plants or Hatch and Slack type plants. The $C_{4}$-plants show Kranz type anatomy, e.g., sugarcane, Corn, Euphorbia, etc.