A seed is a small embryonic plant enclosed in a sheath called the seed coat. They play a key role in the reproduction and spread of multi-cellular flowering plants. A typical seed consists of three parts, an embryo, nutrients for the embryo and a seed coat enclosing the embryo and its nutrients. Seeds are of two types; haploid and diploid. The former has a single set of paired chromosomes while the latter has two paired chromosome sets.
Image courtesy: tiniaki.gr
A spore is a unit of asexual reproduction and form part of the life cycles of bacteria, fungi, algae and other small plants. The spores are also divided into two types; homosporous and heterosporous. The former come in uniform sizes while the latter are further divided into large female spores and small male spores.
Image courtesy: gait.aidi.udel.edu