Apically differentiated region of the flagellum usually composed of 1-3 segments, rarely 4 segments, and exceptionally (Rotoitidae) 6 segments; the claval segments usually are larger in size and/or partly to completely fused; often called the club. [drawing

(L. club): The protuberance on the dorsal surface of the medulla overlying the gracile nucleus. Also known as the Gracile tubercle.

(pl. clavae, adj. clavate) ( Iversen and Troels-Smith, 1950) A club-shaped element of the sexine/ ectexine that is higher than 1µm, with diameter smaller than height and thicker at the apex than the base. See also: baculum, columella, gemma, pilum.