Evolutionary history of plants phloem on the outside. Since xylem cells comprise dead, lignified tissue, subsequent rings of xylem are added to those already present, forming wood. The first plants to develop secondary growth and a woody habit, were apparently the ferns, and as early as the Middle Devonian one species, "Wattieza", had already reached heights of 8 m and a tree-like habit. Other clades did not take long to develop a tree-like stature. The Late Devonian "Archaeopteris", a precursor to gymnosperms which evolved from the trimerophytes, reached 30 m in height. The progymnosperms were the first plants to develop true wood, grown from
Seeds of Peace Peace's work with over 700 young leaders from Maine who are a leading voice for dialogue, inclusion, and equity in schools and communities across the state. Campers take part in an identity-based dialogue program focused on race, religion, economic and educational disparity and other sources of prejudice and discrimination in American society today. The selection process to become a Seeds of Peace camper is very competitive. The selection takes about half a year, with most of the participants being 14-16 years old. Typically, applicants to Seeds of Peace apply through the school systems in their home countries. Applicants must demonstrate