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(nʊˈmæt əˌfɔr, -ˌfoʊr, nyʊ-)

1. a specialized structure developed from the root in certain plants growing in swamps and marshes, serving as a respiratory organ.
2. the air sac of a siphonophore, serving as a float.
pneu•ma•toph•or•ous (ˌnu məˈtɒf ər əs, ˌnyu-) adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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References in periodicals archive ?
The intercalary meristem is situated at the basal portion of the blade, near the junction with the pneumatocyst, and new tissues are constantly moved along the longitudinal axis of the blade (Hoek et al., 1995).
Incidentally, a well-defined lytic lesion was seen in the sacrum adjacent to the left sacroiliac joint consistent with a pneumatocyst.
The reappearance of this kelp was facilitated by spore dispersal, since this species lacks buoyant pneumatocysts that other kelps use to drift tens of kilometers.