(First upload on November 21 2011. Last on July 30 2018) [ 日本語 | English ]

Trapa japonica Flerow

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

⇒ Engler's syllabus (エングラー体系)

Trapaceae L. (ヒシ)

Flower: hermaphrodite, radial symmetry, tetramerous choripetalae
Trapella (ヒシモドキ)
____Hemitrapa (アスナロビシ)
____extinct in Pliocene
____discovered two deformed carpels

These two genra hve not been discovered in the New Continent

↑ affinity of aquatic life

Chrysosplenium: warm-temperate Asia

Trapa: most species in Asian Continent
→ Asian origin

One genus (the taxonomy is controversial)
30 species in the world (2-3 species in Japan)
Annual aquatic forb (+ two genera in Nymphaeaceae
1. floating leaf = 3-6 cm in diameter, dense hair on the veins of backside

2. two spines on the drupe ___ T. japonica
2. four spines on the drupe ___ T. natans L. var. rubeola Makino (メビシ, not in Hokkaido)

1. floating leaf = 1-2 cm in diameter, nearly no hair on the backside ___ T. incisa Sieb. et Zucc.
Trapa L. (ヒシ)
T. bicornis Osbeck (コウモリビシ)

var. bispinosa (Roxb.) Nakano (トウビシ)
var. taiwanensis (Nakai) Z. T. Xiong (タイワンビシ)

T. incisa Siebold et Zucc. (ヒメビシ)
T. japonica Flerow (ヒシ)
T. macropoda Miki (シリブトビシ)
T. natans L. (オニビシ)
T. pseudincisa Nakai (マンセンビシ)

Trapa japonica in Hokkaido

Hishi (ヒシ, 菱), Japanese water chestnut
Lifeform: annual aquatic forb
Distribution: China - Taiwan - Korea - Japan
Habitat: waterlogged wetlands, such as ponds and swamps → wetland (湿原)

Field training on integrated environmental research (統合環境調査法実習) (fauna and flora 種リスト)

Chromosome number: 2n = 96
Edible plant
Trapa japonica Flerow var. tuberculifera (V. Vassil.) Tzvelev
Trapa natans L. var. bispinosa Makino, excl. basion.
Trapa japonica Flerow var. makinoi (Nakano) Ohba, comb. nud.
Trapa bicornis Osbeck var. iinumae (Nakano) Nakano
Trapa bicornis Osbeck var. makinoi (Nakano) Nakano
Trapa bicornis Osbeck var. iwasakii (Nakano) Nakano
Trapa bispinosa Roxb. var. makinoi Nakano
Trapa bispinosa Roxb. var. iinumae Nakano

[1] at Zenibako Coast (銭函海岸), Otaru City, on August 31 2011. [2] in the artificial pond (nicknamed Ono Pond, 大野池), south to the Faculty of Engineer in the campus of Hokkaido University on July 19 2018. [3] in Akanuma Pond, Kushiro Moor, eastern Hokkaido, on June 28 2015.