Children and old people from Southern Brazil have a basic knowledge of plants and microorganisms. Children ages between 4 to 10 (a total of N=366) and old people from 69 to 93 (a total of N=12) were asked to draw what they think is a plant and the children plants plus microorganisms. Afterward, an equal number of boys and girls and old man and women people randomly chosen were interviewed to list plants they knew. This study mostly explore whether children´s drawings accurately reflect their conceptual understanding about plants in a manner that can be interpreted by others. Results demonstrated that children and older pupils held a wide range of conceptions concerning plant structure and function.