Botanists now want us to call Spanish bluebells Hyacinthoides hispanica. But older names persist, including Scilla hispanica; they were also formerly placed in the Endymion genus. The package that you buy at the store may well be labeled Scilla campanulata -- yet another botanical name for the plant.

The scientific names of plants are supposed to make our lives easier as gardeners, giving precision where there would otherwise be chaos. Usually, they live up to their mission statement. Sadly, sometimes botanists have trouble figuring out what botanical name they wish to give a plant. The result is that older literature is littered with the rejected names, as the new name struggles to gain preeminence.

Plant height (and the number of flowers per stalk) will vary according to factors such as the size of the bulb. During the first year that you grow these plants in your yard, the tallest plant may reach 16 inches, while the shortest may stand around 7 inches high (these heights include the floral stalk). Size may diminish in subsequent years. The foliage is basal and sword-shaped, forming a clump.

Source: https://www.thespruce.com/spanish-bluebells-late-blooming-spring-bulb-2132115