Progesterone. Print | Email article to a friend | Last updated: January 14, 2015. Progesterone is a hormone released by the corpus luteum in the ovary. It plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy. It may also be involved in the growth of certain cancers.
Maple helicopters fall before the leaves drop from the trees. Maple trees (Acer spp.) produce winged seeds called double samaras, which twirl to the ground in late summer or early fall. They resemble helicopters in motion, earning them the common name of helicopters or whirligigs.
Spread: 300cm. Time to plant seeds: March to May. Also known as Polygonum baldshuanicum, this has long wiry stems sparsely clad with smallish leaves. The flowers are long airy sprays of creamy white bracts that almost cover the plants from midsummer to autumn.