Butter-and-Eggs is very common in the city, and along roadsides in the suburbs. It can sprout almost anywhere; it blooms for a long time; and it seems impervious to abuse. It’s one of our most beautiful weeds, and if it were at all rarer it would be a treasured garden flower. Father Pitt has accumulated a number of pictures of Linaria vulgaris since 2011, which was the last time we looked at this plant on this site.
Gray describes the genus and the species:
LINÀRIA [Toum.] Hill. TOADFLAX. Calyx 5-parted. Corolla spurred at base on the lower side (in abnormal specimens sometimes regularly 5-spurred). Capsule thin, opening below the summit by 1 or more pores or chinks. Seeds many. —Herbs, with at least all the upper leaves alternate (in ours), flowering in summer. (Name from Linum, the Flax, which some species resemble in their foliage.)
Erect or ascending, with narrow entire leaves.
L. vulgaris Hill. (RAMSTED, BUTTER AND EGGS.) Glabrous, erect, 1.3 m. or less high; leaves pale, linear or nearly so, extremely numerous, subaltérnate; raceme dense; corolla 2-3 cm. long or more, including the slender subulate spur; seeds winged. — Fields and roadsides, throughout our range. (Nat from Eu.)