Cyperus ferax (English spelling) Cyperusferax

Japanese: Cyperus ferax（英語表記）Cyperusferax

...Himekugu is distributed throughout Japan and China, but its basic variety, Taiwan Himekugu K. brevifolia , is a weed distributed almost all over the world from the warm to tropical zones, and is used as pasture grass, and its rhizomes are used in traditional Chinese medicine for colds and pain relief. Kugu is an old name for sedges, but sedges closely related to Himekugu include Mariscus sumatrensis (Retz.) T.Koyama (= Cyperus cyperoides (L.) O.Kuntz.), Torulinium odoratum (L.) S.Hooper (= Cyperus ferax Rich.), and Lipocarpha microcephala Vahl, which are separate genus sedges distributed from the southern part of Honshu to the tropical zones. These have umbels at the top of upright stems and have an appearance closer to that of the Cyperus genus. ...

*Some of the terminology that mentions "Cyperus ferax" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…ヒメクグは日本全国と中国に分布するが，その基本変種であるタイワンヒメクグK.brevifoliaはほとんど全世界の暖帯から熱帯に分布する雑草であり，牧草になるし，根茎は感冒，痛み止めなどに漢方で利用される。　クグとはカヤツリグサ類の古い名称であるが，ヒメクグに近縁のカヤツリグサ類としては本州の南部から熱帯に分布する，それぞれ別属のイヌクグMariscus sumatrensis (Retz.) T.Koyama(＝Cyperus cyperoides (L.) O.Kuntz.)，ムツオレガヤツリTorulinium odoratum (L.) S.Hooper(＝Cyperus ferax Rich.)や，ヒンジガヤツリLipocarpha microcephala Vahlがある。これらは直立した茎の頂に散形花序をつけ，むしろカヤツリグサ属Cyperusに近い外形をとる。…