In a recent article in Discover Magazine, assistant professor in ecology and evolutionary biology, Joe Williams' 10 year long research into angiosperms was recognized as one of the top 100 stories of 2008. 

Angiosperms are flowering plants. Williams did research on the growth rate of pollen tubes, which are responsible for transporting the sperm from the pollen to the egg. 

Angiosperms are special because they comprise over 90 percent of all land plants. They are the most diverse and also the most recently evolved of all major land plant groups. Williams became interested in their evolution because of They have had less time to diversify, yet they are more diverse than any other land plant group. -Joe Williams, assistant professor of ecology and evolutionary biologythe amount that was unknown about them. How did they become so diverse?  When did they veer off from other plants and start rapidly evolving in their own direction?  He wanted to know why they evolved and how it progressed, and through his work he attempted to answer the question of how their reproductive life histories originated and began evolving rapidly.

Angiosperms have at least 12 unique features, but the most defining characteristic is that they have a closed carpel.  The carpel is the seeds' covering, its protective layer. For example, the fleshy walls of a tomato fruit is carpel. The closed carpel is a defining feature of flowering plants.

Angiosperms once belonged to the same group as all other plants, but more than 125 million years ago something changed and they developed carpels. Older species of angiosperms show the presence of an open carpel, whereas younger species have a closed carpel, depicting an obvious evolution over time. 

Many theories have surfaced as to why angiosperms have become such a pervasive group of plants. An early theory was that insect pollination led to specialized relationships between insect and plant, and that one changed to accommodate the other. According to Williams, however, this was not the best theory, since early angiosperms also relied on wind pollination. 

It's interesting that angiosperms have evolved so much faster than other plants since their split with gymnosperms.  "They have had less time to diversify, yet they are more diverse than any other land plant group," Williams said.

Angiosperms have the ability to grow much longer pollen tubes than other plants, which may be the secret to their success as a plant group.  The pollen tube carries the sperm from the pollen to the egg to fertilize the future seed. In angiosperms, unlike all other plants, there is no hard seed shell for the pollen to permeate in order for fertilization to take place.

Williams has been doing field research on the reproductive evolution of angiosperms since 2003.  He has been to many places in the United States, but has also traveled out of the country, doing work in Australia on numerous occasions. 

Williams went to Australia to study the biology of angiosperms. He wanted to see them in action and watch the pollen tubes grow. Williams also performed experimental pollination tests to see how they interacted. With the help of these tests, he wanted to discover if the angiosperms self-pollinated, since the pistil and stamen are quite close together.

If angiosperms originally only self-pollinated, it would have eventually led to their extinction because they could not change and diversify through that sort of reproduction. Flowering plants have such a strong place in the environment and have succeeded as a group for so long, that they must have evolved a mechanism for avoiding self-pollination.

The rapid evolution of angiosperms has led to their takeover of the plant kingdom. They do not need a specialized niche where they can thrive, angiosperms can evolve and adapt to any environment and set roots and Williams' work has increased our understanding of these complicated plants.