Rudolf Steiner. GA 105. Stuttgart. 1908

 Harmony of the Spheres

We can perceive that solar power that descends on the bodies of plants when they grow from the earth with all their roots and leaves, with their final flower, which is washed by the astral body, and in which the spiritual forces of the Sun act; you can perceive them as the spiritual music of the spheres, but this music, of course, can be heard by the spiritual ears.

Spiritual sounds mysteriously penetrate the flower of the plant.

This is the secret of plant life.

... In the seed, the spirit remains hidden, mysterious, but when the seed develops into a plant, then this conditioned and well-fed sound creates the shape of the plant. Looking at our plant kingdom, clairvoyant consciousness sees in the flowers a carpet of the earth's surface, a reflection of solar sounds; therefore, he correctly told Goethe: “The sun sounds in an ancient way.” - So we see how the Universe and the Earth, an immovable star and a planet are spiritually connected.