10. Because the buds weren't open the day before.

9. Because they are day lilies whose genetic coding determines that.

8. Because something eats them.

7. Because there was a tornado.

6. Because the are pumpkin flowers whose genetic coding determines that.

5. Because they are the roses of Atacama whose genetic coding
determines that.

4. Because they are Sacred Datura (members of the nightshade family)
whose genetic coding determines that.

3. Because it is a cactus such as the saguaro and can't waste moisture
by staying open and whose genetic coding determines that.

2. Because it is a Blue passion flower whose genetic coding determines
that.

1. Because there was a frost that night.

Also, the vanilla plant and many others. If the species can survive
with only a one-day bloom, there is no genetic pressure to bloom longer.

--
Pardon my spam deterrent; send email to
Cheers, Steve Henning in Reading, PA USA
http://home.earthlink.net/~rhodyman