semiannular en · ADJ
Etymology
From semi- + annular.
Meanings
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(not-comparable) Having a shape resembling part of a ring or incomplete circular band.
The capsule in both families is spherical, with a bistratose wall; the outer cell layer usually bears nodular thickenings[…]; the inner layer (of nearly equally large cells) lacks the regular semiannular or annular thickenings of most other leafy liverworts[…]
1992, Rudolf M[athias] Schuster, The Hepaticae and Anthocerotae of North America: East of the Hundredth Meridian, volume V, Chicago, Ill.: Field Museum of Natural History, →ISBN, page 6: