Difference between Seeds and Spores

Spores and seeds are the most common reproductive structures found in plants, fungi and some bacteria. They undergo germination to produce new plants or organisms of the same species. Although they serve the same purpose, they are different from each other. Let us see how seeds differ from spores!

Seeds:

A seed is a ripened ovule with a small embryonic plant enclosed in a covering called the seed coat. It is the ovule present in the ovary that develops into the seed after fertilization. A seed basically has three parts embryo, endosperm and seed coat, however some seeds lack endosperm. The endosperm is a source of stored food for the growing embryo and the seed coat comprises one or more protective layers or seed coats to ensure embryo grows into a new plant without being damaged. It is the integuments of the ovule that develop into seed coats. The outer seed coat is called the testa, and the inner seed coat is called the tegmen. In monocots, the seeds have only one cotyledon, whereas, in dicots a seed has two cotyledons.

Spores:

A spore is a reproductive structure, cell or organ of a plant, fungi and algae. It is capable of reproducing and growing into a new plant without involving fusion with other reproductive structures. So, spores are units of asexual reproduction in non-flowering plants, fungi, bacteria, algae etc.

The spores can be of two types: homosporous and heterosporous. In other words, depending on the types of spores produced by a plant, it can be homosporous or heterosporous. If a plant produces only one type of spores, it is known as homospory and if it produces two types of spores (male and female spores), it is known as heterospory.

Based on the above information, some of the key differences between Spores and Seeds are as follows:

Seeds	Spores
They are ripened ovules of a flowering plant.	They are reproductive structures or cells capable of reproducing and growing into a new plant without involving fusion with another reproductive structure or cell.
Seeds are produced by flowering plants.	Spores are produced by fungi, algae, bacteria, non-flowering plants etc.
Seeds are mostly present inside a fruit.	Spores are found underside the leaves of ferns and mosses and gills of the fungi.
They are macroscopic.	They are microscopic.
Seeds are produced in fewer numbers.	Spores are produced in large numbers.
They are of two types based on the number of cotyledons, e.g. monocots produce seeds with single cotyledons and dicots produce seeds with two cotyledons.	They are of two types: homosporous (identical spores or one type) and heterosporous (male and female spores or two different types).
They are multicellular.	They are unicellular.
They are always diploid.	They are always haploid.
Most of the seeds contain reserve food for the growing embryo in the form endosperm.	They lack reserve food or endosperm.
They are mostly dispersed by animals.	They are mostly dispersed by air and water.
They require less water for germination.	The need more water for germination.
They can easily survive in the unfavourable conditions.	Spores are less capable of surviving in harsh conditions.