Make a list of any three outbreeding devices that flowering plants have developed and explain how they halp to encourage cross-pollination.

Explanation

An Angiosperm anthor is called dithecous since theca surround its lobes.
Structure of Microsporangium : In a transverse section a microsporangium appears fairly circular in ouline. It is surrounded by 4 wall layers.
(a) Epidermis.
(b) Endothecium (c ) Middle layers
(d) Tapetum.
The outer three layers of provide protection and Tapetum nourishes the developing pollen grains. The centre of a microsporangium is occupied by sporogenous tissue.