You can use this picture of simple black and white sunflower drawing when you want to create sunflower in pen and ink rendering. A dot method drawing technique used by the artists. If you want a basic tutorial, find sunflower outline, pattern or images and copy or draw them using your pencil.
Sunflower is easy to draw compare to an open rose, the detailed petals, leave and thorn of rose is very complicated to draw. Fine artists can draw rose and sunflower perfectly without a copy on their hand.