The brown seed from the spiny flower-head of the teasel is a favourite food of goldfinches in winter. The genus name, Dipsacus, is derived from the word for thirst and refers to the cup-like formation made where sessile leaves merge at the stem. The first flowers begin opening in a belt around the middle of the spherical or oval flowerhead, and then open sequentially toward the top and bottom, forming two narrow belts as the flowering progresses. The dried head persists afterwards, with the small seeds maturing in mid autumn.Rain water can collect in this receptacle; this may perform the function of preventing sap-sucking insects such as aphids from climbing the stem. The leaf shape is lanceolate, 20-40 cm long and 3-6 cm broad, with a row of small spines on the underside of the midrib.
Text and photograph courtesy of Wikipedia.