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
Naked official abroad (or if they have no spouse, their children) from promotion Naked official Naked official () refers to Communist Party of China officials who stay in mainland China while their spouses and children reside abroad. The Chinese Ministry of Commerce has reported that from the beginning of reform and opening in 1978 to 2003 about 4,000 corrupt officials left China, taking at least $50 billion out of the country; often spouses and children went first. The government is setting up stricter monitoring systems to decrease the practice. In early 2014, a revision of the rules for the promotion and appointment