cocklebur
葹 refers specifically to the cocklebur plant, a type of weedy plant with spiny burs.
葹 combines the plant radical 艹 with 施, which likely provides the sound. The character is used for the cocklebur plant.
The plant radical 艹 on top of 施 suggests a plant that spreads or clings like burs being distributed. Picture a cocklebur plant with its spiny burs sticking to everything.
For シ, imagine a sheep getting cockleburs stuck in its wool: sheep -> シ, and the burs cling to the sheep.