In
botany, the theca is related to plant's flower anatomy. 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. Any part of a
microsporophyll that bears microsporangia is called an
anther. Most anthers are formed on the apex of a
filament. An anther and its filament together form a typical (or filantherous)
stamen, part of the male
floral organ. The typical anther is bilocular, i.e. it consists of two thecae. Each theca contains two microsporangia, also known as pollen sacs. The microsporangia produce the
microspores, which for
seed plants are known as
pollen grains. If the pollen sacs are not adjacent, or if they open separately, then no thecae are formed. In Lauraceae, for example, the pollen sacs are spaced apart and open independently. The tissue between the
locules and the cells is called the
connective and the
parenchyma. Both pollen sacs are separated by the
stomium. When the anther is dehiscing, it opens at the stomium. The outer cells of the theca form the
epidermis. Below the epidermis, the
somatic cells form the
tapetum. These support the development of microspores into mature pollen grains. However, little is known about the underlying genetic mechanisms, which play a role in male sporo- and gametogenesis. '' The thecal arrangement of a typical stamen can be as follows: • Divergent: both thecae in line, and forming an acute angle with the filament • Transverse (or explanate): both thecae exactly in line, at right angles with the filament • Oblique: the thecae fixed to each other in an oblique way • Parallel: the thecae fixed to each other in a parallel way == Zoology ==