The epidermis of petals also form a variation of trichomes called conical cells. These cells all develop from the pavement cells, which make up the majority of the plants surface cells. In short, cellular differentiation of the epidermal cells is controlled by two major factors: genetics and environmental conditions.
Azaleas and rhododendrons thrive in acidic soil. Azaleas and rhododendrons thrive in the acidic soil that is common under pine trees. Both plants are classified under the genus Rhododendron; the main difference is the smaller, funnel-shaped flowers on the azalea.ake soil samples from the area under the trees where you want to plant the azaleas or rhododendrons. Mix the samples in a bucket and test with a soil pH test kit.
Azaleas make up two subgenera of Rhododendron. They are distinguished from true rhododendrons by having only five anthers per flower. The Purple Rhododendron of Washington State is the state flower. It grows naturally all over Western Washington.he Rhododendron genus is the largest of the genera in the Ericaceae family, with 1,024 species, though estimates vary from 850-1000 depending on the authority used, (Fayaz 2012) and is morphologically diverse.