rhizome

Japanese: rhizome

...Dahlias, ranunculus, etc. (5) Rhizome: An underground stem that stores nutrients and thickens. Canna, ginger, German iris, etc.

From [Rhizome]

… In most cases, underground stems are found just below ground level, but in some cases, such as horsetail and lotus, they run horizontally underground at a great depth, and in these cases, air spaces are well developed. Based on their shape, horizontally crawling stems are called rhizomes, globular or globular stems are called tubers and corms, and those with scaly leaves are called bulbs. The underground stems of ferns such as bracken and Japanese white ferns are typical rhizomes, creeping long underground and branching, but there are also rhizomes that grow obliquely or are short and erect. …

From [Stolons]

…Bracken, Chinese fern, bracken, strawberry, and saxifrage are some examples. The underground stolon is also called a rhizome (such as bracken). Stolon is usually branched, with both a main stem and lateral branches, but in some cases, such as bracken, the stem ends in a flower and instead axillary buds grow. …

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

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…ダリア，ラナンキュラスなど。(5)地下茎rhizome　地下茎そのものが養分を蓄えて肥厚したもの。カンナ，ジンジャー，ジャーマン･アイリスなど。…

【地下茎】より

…　地下茎は地面からすぐ下にある場合が多いが，スギナやハスなどのようにかなり深く地中を横走することもあり，これらの場合通気腔が発達している。地下茎はその形状から，横にはうものを根茎rhizome，塊状，球状のものを塊茎tuber，球茎corm，鱗片葉がつくものを鱗茎bulbなどという。シダ類のワラビやウラジロの地下茎は地中を長くはい，枝分れし，典型的な根茎であるが，斜上したり短く直立する根茎もある。…