This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", 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..
Herbs with alternate, usually entire leaves, and violet, blue or white axillary flowers. Calyx 5-parted, the segments narrow. Corolla similar to that of Linaria, but with an open throat and a straight upper lip. Stamens 4, didynamous; filaments slender. Style filiform. Capsule inequilateral, one carpel larger than the other. Seeds ovoid or cuneate, ribbed. [Greek, open nose, referring to the open corolla-throat.]
About 20 species, chiefly in the Mediterranean region and Asia. Type species: Antirrhinum minus L.
Antirrhinum minus L. Sp. Pl. Ed. 2, 852. 1763. Linaria minor Desf. Fl. Atlant. 2: 46. 1800. Chaenorrhinum minus Lange; Willk. & Lange, Prodr. Fl. Hisp. 2: 579. 1870.
Annual, glandular-pubescent all over; stem 5'-13' tall, often branched. Leaves linear-spatulate to linear, mostly obtuse, 5"-15" long, narrowed at the base; flowers shorter than the pedicels, blue or bluish, 2 1/2"- 4" long; calyx-segments linear to linear-spatulate, somewhat shorter than the corolla; spur short and stout, much shorter than the body of the corolla; capsule globose-ovoid.
Waste grounds and ballast, New Brunswick to New York, Pennsylvania and Michigan. Adventive from Europe.