HYAKUDOKU-KUDASI PILL

Rhubarbis the fleshy, edible stalks (petioles) of species and hybrids (culinary rhubarb) ofRheumin the familyPolygonaceae, which are cooked and used for food.The plant is a herbaceousperennialthat grows from short, thickrhizomes.​‍​​​​​‍​‍‍‍‍​‍‍ Historically, different plants have been called "rhubarb" in English. The large, triangularleavescontain high levels ofoxalic acidandanthroneglycosides, making them poisonous and therefore inedible. The smallflowersare grouped in large compound leafy greenish-white to rose-redinflorescences. The precise origin of culinary rhubarb is unknown. The speciesRheum rhabarbarum(syn.R. undulatum) andR. rhaponticumwere grown in Europe before the 18th century and used for medicinal purposes. By the early 18th century, these two species and a possiblehybridof unknown origin,R.×hybridum, were grown as vegetable crops in England and Scandinavia. They readily hybridize, andculinary rhubarbwas developed by selecting open-pollinated seed, so its precise origin is almost impossible to determine.In appearance, samples of culinary rhubarb vary on a continuum betweenR. rhaponticumandR. rhabarbarum. However, modern rhubarb cultivars aretetraploidswith 2n= 44, in contrast to 2n= 22 for the wild species. Rhubarb is avegetablebut is often put to the same culinary uses asfruits.The leaf stalks can be used raw while they have a crisp texture, but are most commonly cooked with sugar and used inpies,crumbles, and otherdesserts. They have a strong,tart taste. Manycultivarshave been developed for human consumption, most of which are recognised asRheum×hybridumby theRoyal Horticultural Society.