Santa Barbara Botanic Garden research associate Sherwin Carlquist, Ph.D., has received the prestigious Grady L. Webster Award in Structural Botany from the Botanical Society of America.

The award was presented to Carquist during national meetings in St. Louis, Mo., July 10-14. This award, given every two years, recognizes the most outstanding paper usually published in the American Journal of Botany in the field of structural and developmental botany (i.e., anatomy and morphology). In this case they made an exception, and it honors Sherwin’s 2009 paper in the Botanical Journal of the Linnean Society titled “Xylem Heterochrony: A Key to Angiosperm Origin and Diversification.”

“It’s very gratifying, not merely because I can still do competent work in my old age (he turned 81 on July 7), but because I think in some ways it’s the most important paper I have written — so far,” Carlquist said.

Charles Darwin said in a letter dated July 22, 1879: “The rapid development as far as we can judge of all the higher plants within recent geological times is an abominable mystery.”

In this quote he was describing the origin of the “evolutionary tree” of flowering plants as an “abominable mystery” because they appear suddenly in the geologic record, but have left very few fossils. The advent of highly credible DNA evidence around the year 2000, combined with microscopic physical evidence examining the “woodiness” (density of the internal anatomy material) of plant samples show that flowering plants began as small plants with little wood.

This runs contrary to the theory accepted throughout the 20th century that woodier flowering plants such as magnolias are more ancient. We now have additional information about what the earliest flowering plants looked like. They looked like waterlilies, irises or peperomias, and had very little wood — but they did have some. Most importantly, they had the ability to develop more wood and various kinds of wood over short periods of geologic time.

These findings were developed by Carlquist, whose extensive work in wood anatomy using scanning electron microscopy as well as light microscopy, enabled this new insight. His article shows that flowering plants, in contrast to conifers and ferns, are able to shift between “juvenile” (minimally woody) and “adult” (clearly woody) wood systems, permitting them to enter a wide range of habitats and take an amazing range of growth forms. This flexible wood system, perhaps more than any other feature, has permitted flowering plants to dominate the world, displacing more ancient groups of plants.

“The significance of Dr. Carlquist’s research has far-reaching implications,” SBBG Executive Director Steve Windhager said. “For the plant, wood is a key tool in dealing with, among other things, drought and freezing and relates to addressing issues in agriculture as well as understanding how some plants may be able to adapt to global climate change.”

The Santa Barbara Botanic Garden is a 78-acre educational and scientific institution fostering the conservation of California’s native plants and serves as a role model for sustainable practice in Santa Barbara.

— Joni Kelly is the communications manager for the Santa Barbara Botanic Garden.