Ruellia is another genus that produces a lot of cleistogamous flowers. The bud you see here is one, and will not open. It will pollinate itself, then produce many seeds. This one was in my garden, where they self seed and spread all too well.
A follow-up to yesterdays mention of polyploidy. Turns out we are partly polyploid. Some of our tissues have constant and difficult jobs. Among those are heart muscle, liver cells, and bone marrow. These cells are able to constantly function because the have multiple control and supply systems. Those are enabled by extra sets of chromosomes. Wow, things get incredibly creative, complicated and amazing!