meristem (n.)youdaoicibaDictYouDict[meristem 词源字典]
"growing cellular tissues of plants," 1862, formed irregularly from Greek meristos "divided, divisible" (from merizein "to divide, distribute," from meros "a part, a share;" see merit (n.)) + ending from xylem, etc.[meristem etymology, meristem origin, 英语词源]