This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol2", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Tall biennial glabrous poisonous herbs, with spotted stems, pinnately decompound leaves, and small white flowers in compound many-rayed umbels. Involucre and involucels of ovate-acuminate bracts. Calyx-teeth obsolete; petals obcordate, or entire with a short inflexed point; fruit broadly ovate, glabrous, somewhat flattened laterally. Carpels strongly wavy-ribbed; oil-tube9 none, but a layer of oil-secreting tissue next the deeply concave seed. [Greek, hemlock.]
One, or perhaps two species, the following typical one native of Europe and Asia, the other of South Africa.
Conium maculatum L. Sp. Pl. 243. 1753.
Erect, much-branched, 2°-5° high. Lower and basal leaves petioled, the upper sessile or nearly so, all pinnately dissected, the leaflets ovate in outline, thin, the ultimate segments dentate, or incised; petioles dilated and sheathing at the base; umbels 1-3' broad, the rays slender, 1'-1 1/2' long; pedicels filiform, 2"-3" long in fruit; flowers about 1" broad; fruit 1 1/2" long, about 1" wide, its ribs very prominent when dry.
In waste places, Nova Scotia to Ontario, Delaware, Indiana and Michigan. Also in California and Mexico, Santo Domingo and South America. Naturalized from Europe. St. Bennet's-herb. Cashes. Wode-whistle. Poison or spotted parsley. Bunk. June-July.