ハブソウは、マメ科に特有の蝶形花ではなく、野趣のある離弁花を咲かせます。種子は生薬の「望江南」。健胃や緩下、利尿に用いられます。
Coffee Senna blooms rustic flowers instead of butterfly-shaped flowers unique to the Fabaceae family. The seeds are used for stomachic, laxative, and diuretic as a herbal medicine.
【仮名】ハブソウ, ボウコウナン
【和名】波布草, 望江南
【英名】Coffee Senna, Negro Coffee
【学名】Senna occidentalis
【誕生】08/ 11
【開花】07, 08月
【花色】Yellow
ハブソウ
ハブソウの概要
ハブソウはマメ科センナ属の１年草。原産地は北米～熱帯アメリカで、日本へは中国を経て江戸時代に持ち込まれました。おもに薬用で栽培される一方、気温が高く、雨の多い亜熱帯の南西諸島や小笠原諸島で野生化。マメ科に特有の蝶形花ではなく、野趣のある離弁花を咲かせます。
ハブソウの名前
ハブソウの名前の由来は「蛇草」。毒蛇に咬まれたときに用いられたからですが、実際には解毒作用がありません。ラテン語の属名センナはアラビア語の「サナ」に由来し、緩下作用のある植物のこと。種小名オキシデンタリスは「西方の」で、欧州から見た原産地の方角を表します。
ハブソウの姿形
ハブソウは無毛の茎が直立します。葉は偶数羽状複葉で互生。小葉は先の尖った披針形です。花は明るい黄色で不整形な花弁５枚の離弁花。雄しべは10本、うち３本が仮雄しべです。花後の豆果は細長く、上を向いて少し湾曲。鞘の中には扁平卵形の種子が２列に並んで入っています。
ハブソウの近縁
ハブソウの近縁種「胡草」は、原産地が北米～熱帯アメリカで、日本へは中国を経て江戸時代に渡来。「恵比須草」や「夷草」とも書かれます。波布草よりも葉先が丸く、豆果が下向き。天日干しの種子が生薬「決明子」になり、目の充血を取り除き、緩やかに便通や排尿を促します。
ハブソウの利用
ハブソウは、天日干しの種子が生薬の「望江南」になり、健胃や緩下、利尿に用いられます。もともと望江南を焙って煎じたものが「波布茶」でしたが、やがて波布草より栽培しやすく、種子も多く採れる「胡草」で代用。一方、ジャマイカでは種子を焙煎して珈琲のように飲みます。
Coffee Senna
Overview of Coffee Senna
Coffee Senna is an annual plant belonging to the Fabaceae family. The place of origin is North America and tropical America, and it was brought to Japan through China in the Edo period. While it was mainly cultivated for medicinal purposes, it grows wild in the subtropical Nansei Islands and Ogasawara Islands, which have high temperatures and a lot of rain. Instead of the butterfly-shaped flower that is unique to the Fabaceae family, it blooms rustic flowers.
Name of Coffee Senna
The Japanese name of Coffee Senna originally means “snake herb”. Because its leaves were used for poisonous snake bites, but it does not actually detoxify. The Latin genus name Senna is derived from the Arabic word “Sana”, referring to the laxative plant. The specific epithet Occidentalis is “western” and refers to the direction of origin as seen from Europe.
Shape of Coffee Senna
Coffee Senna has erect, hairless stems. The leaves are even-pinnately compound and alternate. The leaflets are lanceolate with pointed tips. The flowers are bright yellow and have five irregular petals. There are 10 stamens, 3 of which are pseudostamens. The legumes after flowering are long and slender, slightly curved upwards. The pod contains two rows of flattened ovoid seeds.
Relatives of Coffee Senna
“Oriental Senna”, a closely related species of Coffee Senna, originated from North America to tropical America, and was brought to Japan in the Edo period via China. Leaf tips are rounder than Coffee Senna, and legumes face downward. The sun-dried seeds are used as a herbal medicine to remove redness in the eyes and gently promote bowel movements and urination.
Use of Coffee Senna
The sun-dried seeds of Coffee Senna are herbal medicines that are used for stomachic, laxative, and diuretic purposes. Originally, it was roasted and brewed as a tea, but eventually it was replaced by “Oriental Senna”, which is easier to grow than Coffee Senna and has many seeds. On the other hand, in Jamaica, Coffee Senna seeds are roasted and drunk like coffee.
