Cardamom seeds - cardamom is the common name for certain plant species native to India and southeastern Asia, and is used for their aromatic seeds. The true cardamom has large leaves and white flowers with blue stripes and yellow borders it grows to about 3 m (about 10 ft) in height. The fruit is a small capsule with 8 to 16 brown seeds and the seeds are used as a spice.
Cardamon is a spice popular in Europe and is used in breads and other baked goods. In India the whole pods are used, typically ground, or fried in ghee then used in curries or other dishes.
If you don't have cardamon seeds or just want an alternative you can use half the quantity called for in the recipe of any of these spices (taste and adjust as needed):
Also see equivalents above for replacing the seeds with whole cardamom pods.