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.
A silver maple leaf. The silver maple tree is a relatively fast-growing deciduous tree, commonly reaching a height of 15â25 m (49â82 ft), exceptionally 35 m (115 ft). Its spread will generally be 11â15 m (36â49 ft) wide. A 10-year-old sapling will stand about 8 m (26 ft) tall.he silver maple tree is a relatively fast-growing deciduous tree, commonly reaching a height of 15â25 m (49â82 ft), exceptionally 35 m (115 ft). Its spread will generally be 11â15 m (36â49 ft) wide.