This section is from the book "Nature's Garden", by Neltje Blanchan. Also available from Amazon: Nature's Garden; An Aid To Knowledge Of Our Wild Flowers And Their Insect Visitors.
Flowers - Purple or lilac, small, packed in dense, cylindric heads, 3 to 4 in. long; growing singly on ends of footstalks, the flowers set among stiffly pointed, slender scales. Calyx cup-shaped, 4-toothed. Corolla 4-lobed; stamens 4; leaves of involucre, slender, bristled, curved upward as high as flower-head or beyond. Stems: 3 to 6 ft. high, stout, branched, leafy, with numerous short prickles. Leaves: Opposite, lance-shaped, seated on stem, with bristles along the stout midrib.
Card Teasel (Dipsacus sylvestris)
Preferred Habitat - Roadsides and waste places.
Flowering Season - July - September.
Distribution - Maine to Virginia, westward to Ontario and the Mississippi. Europe and Asia.
Manufacturers find that no invention can equal the natural teazel head for raising a nap on woollen cloth, because it breaks at any serious obstruction, whereas a metal substitute, in such a case, tears the material. Accordingly, the plant is largely cultivated in the west of England, and quantities that have been imported from France and Germany may be seen in wagons on the way to the factories in any of the woollen-trade towns. After the flower-heads wither, the stems are cut about eight inches long, stripped of prickles, to provide a handle, and after drying, the natural tool is ready for use.
Bristling with armor, the teazel is not often attacked by browsing cattle. Occasionally even the upper leaf surfaces are dotted over with prickles enough to tear a tender tongue. This is a curious feature, for prickles usually grow out of veins. In the receptacle formed where the bases of the upper leaves grow together, rain and dew are found collected - a certain cure for warts, country people say. Venus' Cup, Bath, or Basin, and Water Thistle, are a few of the teazel's folk names earned by its curious little tank. In it many small insects are drowned, and these are supposed to contribute nourishment to the plant; for Mr. Francis Darwin has noted that protoplasmic filaments reach out into the liquid.
Owing to the stiff spines which radiate from the flower cluster, the bumblebees, which principally fertilize it, can reach the florets only with their heads, and not pollenize them by merely crawling over them as in the true composite. But by first maturing its anthers, then when they have shed their pollen, elevating its stigmas, the teazel prevents self-fertilization.