わが国の本州以西から四国・九州それに台湾、朝鮮半島南部、中国東南部に分布しています。ふつうは低木ですが、まれに高さが15メートルほどになります。強い剪定にも耐えるため、刈り込みによる整形樹木として利用されています。葉は楕円形から長楕円形で互生し、縁には浅い鋸歯が数個あります。6月から7月ごろ、本年枝の葉腋に淡い黄白色の花を咲かせます。また果実は球形の核果で黒く熟します。和名は「つげ(黄楊)」に似ていて材質が劣ることから。台湾華語では「假黃楊」、中国語では「歯葉冬青(chi ye dong qing)」と呼ばれます。
写真中13、中16〜17、中20〜21は、イヌツゲタマバエがつくった虫えいの「イヌツゲメタマフシ」。
モチノキ科モチノキ属の常緑小高木で、学名は Ilex crenata。英名は Japanese holly。
The Japanese holly (Ilex crenata) belongs to Aquifoliaceae (the Holly family). It is a semi-tall evergreen tree that is native from Honshu west to Shikoku and Kyushu in Japan, as well as Taiwan, the southern Korean Peninsula and southeastern China. This tree is usually a small tree, rarely it can reach about 15 m in height. It is also tolerant severe pruning, and used as a topiary (trees molded into three dimensional forms). The leaves are alternate, elliptic to oblong with several low toothed edges. The pale yellowish-white flowers bloom in the axils of new branches from June to July. The fruits are globose drupes and ripen black. The Japanese common name is derived from "inu" (inferior) + "tsuge" (Japanese boxwood). It is called "假黃楊" in Taiwanese Chinese and "歯葉冬青" (chi ye dong qing) in Chinese.
Photos 14th, 17th-18th, and 21st-22nd show a gall "Inutsuge-metamafushi", an insect fly created by Inutsuge-tamabae.