The seeds of pseudoacacia that Sen had brought back from the world exposition in Vienna were planted in Otemachi in 1875 following his return to Japan, which became the first roadside trees in Tokyo.
仙がウィーン万博から持ち帰ったニセアカシアの種子は、帰国後の明治8年に大手町に植えられ、これが東京初の街路樹となった。