phloem (n.)youdaoicibaDictYouDict[phloem 词源字典]
1870, from German phloëm (1858), coined by German botanist Karl Wilhelm von Nägeli (1817-1891) from Greek phloos, phloios "bark of trees," of uncertain origin, + passive suffix -ema.[phloem etymology, phloem origin, 英语词源]