Morphologic Spice Index

Roots
Stems (rhizomes, barks)
Leaves (including bulbs)
Flowers, fruits and seeds

In this index, I have arranged the spices according to the part of the plant which is used culinarily. In case several parts of a plant have aromatic qualities, I list the spice under each part suitable for cooking.

All plant structures, however specialized, can be derived from one and only one of the four basic plant organs root, stem, leaf and flower. Reflecting this fundamental quadrisection of the plant organism, this index is partitioned in four sections, with finer subsectioning as appropriate.

Roots:
Root spices are, rather surprisingly, rare. Although all of the plants listed here have aromatic roots, most of them are better known as herb or fruit spice.
If you look for a specific root spice and can’t find it here, then maybe it's not a root but a rhizome .
Stems:
Pure stem spices are uncommon: Stems tend to be woody and unfriendly to eat, so the leaves are preferred. However, some subterranean fleshy stems known as rootstocks or rhizomes, form valuable spices. And, there are some aromatic barks as well.
- Rhizomes:
- Barks:
Leaves:
In case of herbs, it is rather common to harvest stem, leaves and possibly flowers together, although the leaves are the most fragrant part. Bulbs are special subterranean reserve structures derived from leaves.
Flowers
Although most entomophilous flowers are somewhat fragrant, only few of them are used in the kitchen, because they usually lose their scent quickly when dried. The ripe form of flowers, fruits, are also frequently aromatic, but mostly not to attract insects but to repel them.