Digitalis purpurea nectar within. The fruit is a capsule which splits open at maturity to release the numerous tiny 0.1-0.2 mm seeds. The three subspecies of "Digitalis purpurea" are: Due to the presence of the cardiac glycoside digitoxin, the leaves, flowers and seeds of this plant are all poisonous to humans and some animals and can be fatal if ingested. Extracted from the leaves, this same compound, whose clinical use was pioneered by William Withering, is used as a medication for heart failure. He recognized it "reduced dropsy", increased urine flow and had a powerful effect on the heart. Unlike the purified
Plant as rayon and acetate derived from plant cellulose. Thread used to sew cloth likewise comes in large part from cotton. Thousands of plant species are cultivated for aesthetic purposes as well as to provide shade, modify temperatures, reduce wind, abate noise, provide privacy, and prevent soil erosion. Plants are the basis of a multibillion-dollar per year tourism industry, which includes travel to historic gardens, national parks, rainforests, forests with colorful autumn leaves, and festivals such as Japan's and America's cherry blossom festivals. While some gardens are planted with food crops, many are planted for aesthetic, ornamental, or conservation purposes. Arboretums