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.
Sugar maples provide stunning fall color in bright shades of yellow, orange and red. The deciduous sugar maple tree reaches up to 100 feet high with a spread of 50 feet and lives up to 400 years.A native to Eastern North America, the sugar maple (Acer saccharum) grows in U.S. Department of Agriculture plant hardiness zones 4 through 8. This variety of maple provides the sap for making maple syrup.tratify the sugar maple seed using your refrigerator or other cold location with temperatures between 33 and 46 degrees Fahrenheit. Leave the seed to stratify for up to 90 days, checking weekly for germination.