Heterospory:
Selaginella is a heterosporous plant, meaning it produces two types of spores - microspores and megaspores. This characteristic is similar to gymnosperms, which also exhibit heterospory. In both Selaginella and gymnosperms, the microspores develop into male gametophytes and the megaspores develop into female gametophytes. This is in contrast to homosporous plants, such as ferns and mosses, where a single type of spore develops into both male and female gametophytes.

Vascular Tissues:
Both Selaginella and gymnosperms possess vascular tissues, specifically xylem and phloem. Xylem is responsible for the transport of water and minerals from the roots to the other parts of the plant, while phloem transports sugars and other organic molecules from the leaves to the rest of the plant. The presence of vascular tissues allows for efficient long-distance transport within the plant and provides structural support.

Cone:
Selaginella does not produce cones, but it does possess structures called strobili that are similar in function to cones in gymnosperms. These strobili are compact clusters of sporophylls that bear the sporangia where spores are produced. Gymnosperms, on the other hand, have cones that contain the reproductive structures. While the specific structure and appearance of cones may differ between Selaginella and gymnosperms, they both serve the purpose of housing and protecting the reproductive organs.

All of the above:
Considering the similarities in heterospory, vascular tissues, and cone-like structures, it can be concluded that Selaginella is alike to gymnosperms in all of these aspects. These similarities indicate a closer evolutionary relationship between Selaginella and gymnosperms compared to other plant groups. This is further supported by molecular and genetic studies that have revealed shared ancestry and genetic similarities between Selaginella and gymnosperms.