The tetrads of D. clavatus are tetrahedral and 34–40 μm in diameter. Individual grains are subspheroidal and measure 18–25 μm in width. They have a roughly circular amb that is abruptly acute at the distal pole. The exine is 0.5–1 μm thick, with 2–3 μm long clavae or bacula.[1]
^Song, Z.-C., W.-M. Wang & F. Huang 2004. Fossil pollen records of extant angiosperms in China. The Botanical Review70(4): 425–458. doi:10.1663/0006-8101(2004)070[0425:FPROEA2.0.CO;2]