Theca

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theca

[′thē·kə]
(anatomy)
The sheath of dura mater which covers the spinal cord.
(botany)
A moss capsule.
A pollen sac.
(histology)
The layer of stroma surrounding a Graafian follicle.
(invertebrate zoology)
The test of a testate protozoan or a rotifer.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Theca

 

various types of sheath in animals and plants:

(1) A cell wall in certain amoebae (thecamoebae).

(2) A chitinoid membrane in hydroid polyps; hence the division into the suborders Thecaphora and Athecata.

(3) The connective tissue surrounding ovarian follicles in vertebrates (theca folliculi).

(4) A tooth socket in the jawbone of mammals and crocodiles.

(5) A capsule for spores in mosses.

(6) The valve of a silicified test; in diatoms, the upper half is the epitheca and the lower half, the hypotheca.

(7) The pollen sac of an anther in angiosperms.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Concerning the content, the reader finds a thorough study of the late Phoenician tradition of inhumating the dead in thecae and anthropoid sarcophagi.
The number of thecae in species of this lineage varies from 18 in older taxa to three pairs in the youngest forms.
acuta has differentiated inner and outer thecae. There are many studies about the stereidogenic capacity of this tissue and there are differences among species referring to which the thecal layer has this capacity (Koob and Callard, 1999).
Herba annua 8-30 cm alta; folia decussata, lamina 11-25 mm longa, 6-18 mm lata, petiolo 1-5 mm longo; flores axillares, 1 in axilla, 2 per nodum; pedicelli 3-11 mm longi; calyx 4-sectus, segmentis inaequalibus, ciliatis, 1.7-2.5 mm longis, 1.1-2 mm latis; corolla lutea vel luteo-aurantiaca, sine maculis, labio superiore curvato, 1.5-2 x 2-2.5 mm, labio inferiore sacciforme, 3.5-5.5 x 3.2-5 mm; elaeophorus adest; stamina filamentis laminatis 1.5-2 mm longis, antherae 0.5-0.75 mm longae, 0.4-0.5 mm latae, thecae aequales, divaricatae vel leviter deflexae, totae dehiscentes; capsula turbinata 4.3-7 x 3-3.9 mm; semina ellipsoidea 0.4-0.5 x 0.2-0.3 mm, glabra.