What flowers appear in one of Vincent van Gogh's most famous paintings?

Many would say Sunflowers, (15) yet others would say Irises, you be the judge, here is a site and an excerpt for a little research:

The most famous and most expensive of these sales is that of the Portrait of Dr. Gachet, sold in 1990 for $82.5 million, equivalent to $130 million today. The painting's whereabouts are currently unknown though. Other paintings of Vince Van Gogh's to have sold for more than $50 million include Irises sold for $53.9 million in 1987, Portrait de l'artists sans barbe sold for $71.5 million in 1998, A Wheatfield with Cypresses sold for $57 million in 1993, Vase with Fifteen Sunflowers sold for £24.75 million in 1987, and Peasant Woman Against a Background of Wheat sold for $60.8 million in 1997.

* http://www.aspectart.com/info/