The most important Nishapur souvenirs include turquoise and rhubarb.
Rhubarb (Rheum rhabarbarum) is a species of plant in the family Polygonaceae. They are herbaceous perennials growing from short, thick rhizomes. They have large leaves that are somewhat triangular, with long fleshy petioles. They have small flowers grouped in large compound leafy greenish-white to rose-red inflorescences.
In culinary use, fresh raw petioles (leaf stalks) are crisp (similar to celery) with a strong, tart taste. Most commonly, the plant's leaf stalks are cooked with sugar and used in pies and other desserts. A number of varieties have been domesticated for human consumption.
Rhubarb is usually considered a vegetable. Rhubarb contains anthraquinones including rhein, and emodin and their glycosides (e.g. glucorhein), which impart cathartic and laxative properties. It is hence useful as a cathartic in case of constipation.
Rhubarb (Persian rivaas or rivand), a sour vegetable, grows at the foot of the eponymous Rivand Mountains (more recently, Turkified as Mount Binalud). Soft drinks made from the stems of the plant, such as "Sharbate rivaas" and "Khoshaabe rivaas" , are sold at some Nishapur resorts ...see more as souvenirs.
Commonly, it is stewed with sugar or used in pies and desserts, but it can also be put into savory dishes or pickled. Rhubarb can be dehydrated and infused with fruit juice. In most cases, it is infused with strawberry juice to mimic the popular strawberry rhubarb pie.
Rhubarb root produces a rich brown dye similar to walnut husks.