Dryandra subg. Diplophragma facts for kids

Dryandra subg. Diplophragma was once a special group of plants, like a smaller division, within the larger Dryandra plant family. Today, Dryandra plants are actually part of the Banksia family, specifically called Banksia ser. Dryandra. This group, Diplophragma, was first named by a botanist named Robert Brown in 1830. However, another botanist, George Bentham, decided it wasn't a good group in 1870. Later, in 1996, Alex George brought it back with a new idea of what plants belonged in it. But finally, in 2007, Diplophragma was removed again when all Dryandra plants were moved into the Banksia family by Austin Mast and Kevin Thiele.

Early Ideas: Brown's Classification

In 1830, Robert Brown first described Diplophragma. He thought this group was special because of how many "seed separators" it had. Seed separators are like little barriers inside the fruit that divide the seeds. Brown believed Diplophragma had two of these barriers.

He placed only one plant species in this group: D. bipinnatifida. This plant is now known as Banksia bipinnatifida. The name Diplophragma comes from Greek words: diplo meaning "two" and phragma meaning "barrier." Interestingly, Brown was mistaken; this plant actually has no seed separators at all!

Meissner's Changes: Adding More Plants

Later, in 1856, another botanist named Carl Meissner looked at the Dryandra plants again. He kept Brown's Diplophragma group. Meissner added a new feature to define the group: the leaves had to be "bipinnatifid." This means the leaves are deeply divided, and then those divisions are divided again, making them look very feathery.

Meissner also added another plant to the Diplophragma group: D. preissii. This plant is now called Banksia acuminata.

Bentham's Decision: Discarding the Group

In 1870, George Bentham decided to remove the Diplophragma group. He noticed that the "seed separator" feature, which Brown had used, wasn't always the same in different plants. He also realized that the two plants Meissner had placed in Diplophragma (D. bipinnatifida and D. preissii) were not actually closely related.

Bentham moved D. bipinnatifida into a different group called D. sect. Aphragma. He placed D. preissii in another group called D. sect. Eudryandra ser. Niveae.

George's Revival: A New Look

In 1996, Alex George published his own study of Dryandra. He saw that D. bipinnatifida had many unique features, especially in its fruit. Its seed pods and seeds were unusually large. The seeds also had special double wings attached to them. Plus, the plant had very long bracts (leaf-like structures near the flowers).

Because D. bipinnatifida was so different, George felt it needed its own special group. So, he brought back Diplophragma, but this time as a "subgenus" (a higher rank than a section). He called it D. subg. Diplophragma, and it contained only D. bipinnatifida (which is now Banksia bipinnatifida).

Recent Changes: Joining the Banksia Family

Since 1998, a scientist named Austin Mast has been studying the DNA of Banksia and Dryandra plants. His research showed that Dryandra plants actually grew out of the Banksia family. This means Dryandra wasn't a completely separate group.

In 2007, Mast and Kevin Thiele decided to combine Dryandra into Banksia. They made Dryandra a series within Banksia, called Banksia ser. Dryandra. Because of this big change, all the old groups within Dryandra, including D. subg. Diplophragma, are no longer used. Scientists are still working on a new way to organize these plants based on their DNA.