Cornell is offering a new course and I'm registered! Botanical Illustration 3: Advanced Techniques. We'll be touching upon lots of media--pencil, charcoal, chalk, pastel, colored pencil. Exciting! See the full syllabus for all the details.
Here's the full list of Cornell's online horticultural courses. Check out the Botanical Illustration 1 course for an image of one of my drawings from that course.