Globe Thistle
Sphaeranthus suaveolens ?
Spreading to decumbent stems and inflorescence (this photo is rotated 90°). Secondary woods. Nairobi, Kenya. July 2015.
These plants take the concept of a composite one step further: Very small heads of purple flowers are themselves clustered into dense spherical heads. The plants are mostly herbaceous with weak stems that may fall over and clamber along the ground and taking root at the nodes. The other curious trait are the leaf-like wings that extend down the leaf petioles and along the stems. These wings and the leaves are sharply toothed.