Some dioecious plants determine sex by sex chromosomes (XY or ZW) like mammals or birds. A pair of birds on branches of a pine tree, which is a symbol of a new year in Japan, is a couple of Eclectus parrots (Eclectus roratus) having extreme sexual dimorphism (left: ZZ male; right: ZW female). What they hold in their beaks are flowers of 'Suiba' (common sorrel or Rumex acetosa; left: XY1Y2 male; right: XX female). Suiba is one of the first species among the seed plants whose existence of sex chromosomes was reported (H. Kimura & T. Ono (1923) Bot. Mag. (Tokyo) 37(438), 147-149. DOI: 10.15281/jplantres1887.37.438_147). It is known that Suiba's sex determination system is similar to that of Drosophila and depends on the ratio of X chromosomes to autosomes.
Genpaku Sugita (1733-1817) is well-known for his translation of 'Kaitai Shinsho' (New Text on Anatomy, in 1774) compiled based on a book of anatomy written in Dutch. This Japanese first full-blown translation from a Western language contributed to the development of medical science in Japan. The masterpiece has been accomplished while many translated terms such as "shinkei" (= nerve) were coined. Over the past 240 years since then, anatomical methods have dramatically improved. Various optical clearing agents have been invented to clear organs including the brain without difficulty. Now, those agents can make brains transparent without damaging any of the fine structures, and enable researchers to observe neurons deep inside the brain. With our great respect to Genpaku Sugita, let us give him components of the optical clearing agents: urea, detergents and aminoalcohol. Behind him stands a vase of a soapberry tree bearing fruit that used to be raw material for detergents in Edo era.