Differentiate between the following pair of the terms testa and tegmen?

Testa and tegmen are botanical terms related to seeds, specifically the structures that surround and protect the embryo within a seed. Here's the differentiation between the two terms:

Testa:

The testa, also known as the seed coat, is the outermost layer of a seed.
It is derived from the integuments of the ovule after fertilization.
The testa provides protection to the embryo and the endosperm inside the seed from mechanical damage, pathogens, and other external factors.
It is often hard, tough, and impermeable to water, helping to prevent premature germination and dehydration of the embryo.
The testa can have various textures, colors, and patterns, which can aid in seed identification.
Tegmen:

The tegmen is an inner layer of the seed coat that is located directly adjacent to the embryo.
It is also formed from the integuments of the ovule, like the testa.
The tegmen is typically thinner and softer than the testa, and it is often closely adhered to the seed coat.
While the primary role of the tegmen is protection, it is more intimately associated with the embryo and often remains attached to the embryo when the seed germinates.
The tegmen is not always present in all seed types, and its presence can vary depending on the plant species.
In summary, the testa is the outermost layer of the seed coat, providing protection and often having a tougher, impermeable structure. The tegmen is an inner layer of the seed coat, situated next to the embryo, and is typically softer and closely associated with the embryo's development. Both structures work together to safeguard the embryo and facilitate successful seed germination.