The seaweed Kappaphycus alvarezii is hard, meaty, and rough. The diameter of its coarse thalli is around 1/2 inch. The thalli are hefty, lack secondary branches close to the tips, and have primary axes that are generally straight. It has several sporadic and erratic branches, the majority of which are primary. Up to 2 meters tall, it is. shiny green to orange-yellow in hue.