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.
Amur Maple - Acer ginnala. The Amur maple leafs out in early spring, is easy to transplant, is relatively pest free and casts dense shade. Hardiness Zones: 5-7, deciduous, growth rate: slow, site requirements: Sun; prefers well drained soil. Form: Vase shaped. Easy to transplant; relatively pest free; good fall color.