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Diatoms of North America
Practitioners
Morphology
Centric
Araphid
Eunotioid
Symmetric Biraphid
Monoraphid
Asymmetric Biraphid
Epithemioid
Nitzschioid
Surirelloid
Genera
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Glossary
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What are diatoms?
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Round_1990_theca.jpg
Glossary Term
Theca
Caption
A frustule is composed of two valves and its component parts, termed epitheca and hypotheca.
Credit
Adapted from Round et al. 1990
