Every Day Is Special: January 14 – Happy Birthday, Adolphe-Theodore Brongniart

January 14 – Happy Birthday, Adolphe-Theodore Brongniart

Posted on January 14, 2015

The father of paleobotany.

That's quite a title! But Adolphe-Theodore Brongniart (who was born in Paris, France, on this date in 1801) was a pioneer in his efforts to compare extinct and existing plants.

Since paleo- means "ancient" and botany means "the study of plants," paleobotany is the name for the study of remains of ancient plants.

Brongniart did two things very well indeed:

He investigated his subject thoroughly. That means that he studied many different plant fossils as well as extant plant species (kinds of plants that are living today).

He wrote a lot. He wrote books and memoirs. Because of his careful note taking during his investigations, scientists were able to publish his findings on fossil seeds even though Brongniart had died before he could do so.

Some people think of fossils as hard things like bones and teeth and shells...and they might wonder how plants could ever become fossils. After all, they don't have bones or teeth or shells!

Indeed, most plants do not become fossilized. Most organisms (including plants and animals) that have lived and died do not become fossils because they are either eaten by animals or decomposed by microorganisms. The hard parts like shells are less likely to be eaten and also decompose more slowly. If a dead organism is quickly buried before it is eaten or decomposed, then it has a much better chance of becoming a fossil. Sometimes even the soft parts of an organism is fossilized because the animal or plant was buried so quickly.

It's important to also understand that fossils are generally not the actual bones, teeth, or shells, but are instead rocks in which the structures of the organism are preserved because organic molecules that made up the organism were replaced by minerals, one molecule at a time. This mineral replacement process can happen with trees or other plants, in the right conditions. Many people call fossilized trees “petrified wood.”

Here are some of the ways that plants can become fossils:

Impressions.

The most common sort of plant fossil is an impression of a flattened plant or plant part. These sorts of fossils often show a lot of anatomical detail of the plant.

Molds and casts.

Some seeds, cones, or woody stems can be preserved (at least partly) by sediment entering hollow portions of the plant, creating a sort of mold and cast. Generally these sorts of fossils do not provide much evidence of internal structures or detailed anatomy.

Petrification.

This is that slow mineralization process I talked about above.

Fussain.

Although fire usually destroys plant tissues, sometimes there are delicate "charcoalified" remains that reveal plant structures such as flowers.