Theca

The theca of an angiosperm consists of a pair of microsporangia that are adjacent to each other and share a common area of dehiscence called the stomium.

The thecal arrangement of a typical stamen can be as follows: In biology, the theca of follicle can also refer to the site of androgen production in females.

The theca of the spinal cord is called the thecal sac, and intrathecal injections are made there or in the subarachnoid space of the skull.

In human embryogenesis, the theca cells form a corpus luteum after a Graafian follicle has expelled its secondary oocyte arrested in second meiosis.

In microbiology and planktology, a theca is a subcellular structural component out of which the frustules of diatoms and dinoflagellates are constructed.