Final answer:
Asters, Calla Lilies, and Hydrangeas are all flowering plants or angiosperms that come from a common ancestor and display diverse morphology yet with similar basic structures. Hydrangeas are especially interesting as their flower color can change based on soil pH, showing the relationship between biology and chemistry.
Step-by-step explanation:
Asters, Calla Lillies, and Hydrangeas are examples of flowering plants, also known as angiosperms, which are classified under Kingdom Plantae, Phylum Magnoliophyta or Anthophyta. These flowering plants have evolved from a common ancestor, exhibiting different forms while maintaining a basic morphology that includes structures such as the calyx, carpel, and often colorful petals that attract pollinators. Specifically, Hydrangeas are noted for their ability to have different colored flowers due to soil pH impacting the availability of aluminum ions, demonstrating chemical equilibria in the garden.
The study of angiosperms also includes understanding their phylogeny and taxonomy, with aster being part of a large family, Asteraceae. The common Hydrangea macrophylla species in this family, for example, shows different colored flowers, which depend on the soil pH levels. This variation in color is a great illustration of the interplay between biology and chemistry in horticulture.