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.
Comments. Submit. Baby pine trees are called seedlings. Foresters use seedlings to regenerate pine tree forests after mature tree removal. Baby pine trees become saplings when the plant reaches 1 to 2 feet high and about 1 inch in diameter.Keywords: baby pine trees, seedling pine trees, sapling pine trees.oresters use seedlings to regenerate pine tree forests after mature tree removal. Baby pine trees become saplings when the plant reaches 1 to 2 feet high and about 1 inch in diameter.