Taxonomic Categories and their Characteristics:

Monocotyledonae:
- Monocotyledonae is a class of angiosperms that have a single cotyledon in their seeds.
- They have parallel venation in their leaves.
- Their floral parts are in multiples of three.
- Examples include grasses, lilies, orchids, and palms.

Sapindales:
- Sapindales is an order of flowering plants that includes trees, shrubs, and lianas.
- They have specialized hairs or scales on their leaves, stems, or fruits.
- Their flowers are usually small and have five sepals and five petals.
- Examples include maple, lychee, and citrus trees.

Poales:
- Poales is an order of monocotyledonous flowering plants that includes grasses, sedges, and rushes.
- Their leaves are usually long and narrow with parallel veins.
- Their flowers are usually small and inconspicuous with wind-pollinated flowers.
- Examples include wheat, rice, and bamboo.

Primata:
- Primata is an order of mammals that includes lemurs, monkeys, apes, and humans.
- They have opposable thumbs, binocular vision, and a large brain relative to their body size.
- They have nails instead of claws and most are arboreal.
- Examples include chimpanzees, gorillas, and humans.

Explanation:
The odd one out of the given taxonomic categories is 'Monocotyledonae' because it is a class of angiosperms, while the other three options are orders of flowering plants and mammals. The other three options also share common characteristics such as specialized hairs or scales on their leaves, stems or fruits, small and inconspicuous flowers with wind-pollinated flowers, or opposable thumbs, binocular vision, and large brain relative to their body size. Therefore, 'Monocotyledonae' is the odd one out in this case.