Botanical Gardens

I am on my way to my college reunion at Oberlin College in Ohio. A number of us spent a couple of days at a pre-reunion in nearby Cleveland. Yesterday some of us visited the Botanical Gardens, which are wonderful. I did this sketch (which gave me a workout on creating different shades of green) while sitting in the cloudforest greenhouse. Every afternoon they release more butterflies into the greenhouse. How many butterflies can you count in this sketch?