Which plant is known for its tall spikes of purple flowers and is commonly referred to as Foxglove?

Digitalis is indeed the plant commonly referred to as Foxglove. This genus is well-known for its striking tall spikes adorned with tubular flowers, which are primarily purple but can also appear in shades of pink, white, and yellow. The flowers of Digitalis are arranged in a raceme, and they are particularly attractive to pollinators like bees.

In horticulture, Foxglove is appreciated not only for its aesthetic appeal in garden settings but also for its medicinal properties, as it contains compounds that have been used to treat heart conditions. However, it is important to handle this plant with care, as it is also toxic if ingested.

The other plants mentioned may have their distinct features, but they do not match the description of having the characteristic tall spikes of purple flowers associated with Foxglove. Echinacea purpurea, for instance, is known for its prominent cone-shaped flower heads and is distinct in its flowering structure. Delphinium produces tall flower spikes in a variety of colors but typically does not have the same tubular flower shape attributed to Digitalis. Helleborus, or Christmas rose, has a very different form and flowering habit, blooming much closer to the ground and primarily in the winter or early spring.