Characteristics
Cow Parsnip is a tall herb, reaching to heights of over two meters. The genus name Heracleum (from "Hercules") refers to the very large size of all parts of these plants. Cow Parsnip has the characteristic flower umbels of the carrot family (Apiaceae), about 20 cm across; these may be flat-topped, as in the pictures above, or more rounded, and are always white. Sometimes the outer flowers of the umbel are much larger than the inner ones, as in the top image. The leaves are very large, up to 40 cm across, divided into lobes (see image). The stems are stout and succulent. The seeds are 8-12mm long and 5-8mm wide (seedheads shown in image).
Read more about this topic: Heracleum Maximum