ragweed

Isabella Birdの "Unbeaten Tracks in Japan" を読んでいます。
We took three horses and a mounted Aino guide, and found a beaten track the whole way. It turns into the forest at once on leaving Sarufuto, and goes through forest the entire distance, with an abundance of reedy grass higher than my hat on horseback along it, and as it is only twelve inches broad and much overgrown, the horses were constantly pushing through leafage soaking from a night’s rain, and I was soon wet up to my shoulders. The forest trees are almost solely the Ailanthus glandulosus and the Zelkowa keaki, often matted together with a white-flowered trailer of the Hydrangea genus. The undergrowth is simply hideous, consisting mainly of coarse reedy grass, monstrous docks, the large-leaved Polygonum cuspidatum, several umbelliferous plants, and a “ragweed,” which, like most of its gawkv fellows, grows from five to six feet high. The forest is dark and very silent, threaded by this narrow path, and by others as narrow, made by the hunters in search of game. The “ main road ” sometimes plunges into deep bogs, at others is roughly corduroyed by the roots of trees, and frequently hangs over the edge of abrupt and much-worn declivities, in going up one of which the baggage-horse rolled down a bank fully thirty feet high, and nearly all the tea was lost. At another the guide’s pack-saddle lost its balance, and man, horse, and saddle went over the slope, pots, pans, and packages flying after them.

Isabella Birdは植物にも詳しいですね。学名の植物はとうてい覚えられませんが、通称名らしい "ragweed" は覚えたい。辞書の説明を見ます。
・Oxford English Dictionary: A North American plant of the daisy family. Its tiny green flowers produce copious amounts of pollen, making it a major causative agent of hay fever in some areas.: People who have known sensitivities to ragweed may experience reactions to chamomile and should use caution.

・Collins Dictionary: Ragweed is a plant, found mainly in North America, that produces large amounts of pollen, which causes hay fever.: ...an allergic reaction to a particular type of ragweed

昔から花粉症に悩まされていて、四十年以上前ですが、医者から原因はセイタカアワダチソウだと言われましたが、最近の説ではセイタカアワダチソウは花粉症の原因にはなり難く、ブタクサ（つまり “ragweed”)だった可能性が高い。　しかし幸いなことに、十年程前から不思議なことに花粉症（そして喘息も）は出なくなったのです。