South Africa / Kalahari / yellow flower with main branch on the ground

Hello,

Here is a flower seen in the South African Kalahari during the rainy season at the end of january.
There were quite a few in the same concentrated area near the camp of Twee Rivieren in the Kgalagadi National Park.
If someone has an idea of the name ..
Thank you

 

Hi,
looks like Cassia / Senna italica...

 

Thank you Lila,
That's the one
Cheers