What are the features of gymnosperms from other higher plants?

Gymnosperms are the oldest seed-propagating plants that have survived to this day. They appeared on Earth about 350 million years ago and retained some archaic properties, which makes them different from other groups of plants. For example, they differ from angiosperms in the absence of a soft protective coating, flowers and fruits. They differ from spore ones in that, instead of the gametophyte phase, seed fertilization occurs in gymnosperms. The most common gymnosperms are conifers.