しろよもぎ (白蓬) [Index] [Back] わが国の本州、新潟県・茨城県以北から北海道、それに朝鮮半島やロシアの極東地方、アメリカのアリューシャン列島に分布しています。日当たりのよい海岸の砂地に生え、高さは２０〜６０センチになります。茎は直立または斜上し、白色の綿毛に被われます。葉は銀灰色で倒披針形、羽状に中裂し、白色の密な綿毛があります。８月から１０月ごろ、円錐花序に黄色い頭花を咲かせます。頭花には舌状花がなく、筒状花のみで構成されています。果実は狭長円状線形の痩果です。和名は、全体が白い綿毛で被われ、雪白色になるためです。  キク科ヨモギ属の多年草で、学名は Artemisia stelleriana。英名は Beach wormwood、Dusty-miller。  The Beach wormwood (Artemisia stelleriana) belongs to Asteraceae (the Aster family). It is a perennial herb that is distributed from Niigata and Ibaraki prefectures of Honshu northward to Hokkaido in Japan, the Korean Peninsula, the Far East region of Russia, and the Aleutian Islands in the United States. It grows in sandy soil on sunny coasts and is 20 to 60 cm tall. The stem is erect or oblique and covered with white wooly hairs. The leaves are silvery gray, oblanceolate, pinnately lobed, and densely covered with white wooly hairs. Yellow flower heads bloom in conical panicles from August to October. The flower heads have no ray florets and are composed only of tubular flowers. The fruit is a narrowly oblong-linear achene. The Japanese name is derived from its snow-white color, which is entirely covered with white wooly hairs.  北海道函館市「立待岬」にて、2023年08月25日撮影。  Shu Suehiro shu@botanic.jp