The snapdragon and plantain family
Plantaginaceae is named after a weed that grows out of a crack in a parking lot, and it now holds the snapdragon, the foxglove and a good share of the vertical flowers in a florist's cooler. It is the clearest case on this site of a family that looks nothing like its own name.
around 95 genera
roughly 1,900 species
Worldwide, on every continent except Antarctica
Everything in this guide that belongs to Plantaginaceae
Plantago is the ribwort and broadleaf plantain, a flat rosette with a stubby brown flower spike, and its distinction is surviving being walked on. For a long time the family named after it held little else, while snapdragons, foxgloves, penstemons and veronicas sat together in a large and untidy Scrophulariaceae, the figwort family.
Molecular work in the late 1990s took Scrophulariaceae apart. Most of its familiar garden and florist genera turned out to belong with Plantago rather than with figwort, and because the older name has priority the whole enlarged group is Plantaginaceae. It is one of the biggest reshuffles in modern plant classification, and it is why an older reference book files a snapdragon somewhere else entirely.
There is no single character running through the whole family, and pretending otherwise would be dishonest. Most members share flowers fused into a two lipped or spurred tube, four stamens in two unequal pairs, and a dry capsule holding a great many small seeds.
Squeeze a snapdragon flower gently at the sides and it opens like a mouth, which is the whole reason for the name and the reason children have always played with them. It is not a trick for people, though. The flower is held shut by the lower lip pressing up against the upper, and parting them takes real force.
That force is a bumblebee. A honeybee is neither heavy enough nor strong enough to lever the lips apart, so it is shut out, while a bumblebee lands on the lower lip, pushes in, collects and delivers pollen against the roof of the flower and backs out again. The plant has effectively chosen its pollinator and closed the door on everyone else. Antirrhinum, the genus name, is Greek for nose like, which is what a spent flower resembles once the seed capsule has formed.
Snapdragons are the most strongly geotropic flower most florists handle. Lay a bunch on a bench, go home, and by morning every tip will have curled upward into a hook that will not straighten out. The growing tip senses gravity and responds within hours, and the bend is permanent because the stem has grown into it. The rule has no exceptions: snapdragons stand up, in the box, in the bucket and in the cooler.
Veronica shares the habit in a milder form, and shares the other spike characteristic as well. Both open from the bottom of the spike upward, so a stem bought half open goes on giving for days, and both keep extending at the tip while they do it. Pick the spent lower florets off rather than pulling the whole stem.
Both are also sensitive to ethylene, and a snapdragon shows it by shattering, dropping sound florets off a stem that still looks fresh.
Penstemon, chelone, angelonia, linaria, hebe and the aquatic mare's tail are all in this family, and so is Digitalis, the foxglove. Foxglove is worth naming precisely because it is beautiful and is sometimes cut for arrangements. It contains cardiac glycosides, the compounds that gave medicine digoxin, and they act directly on the heart.
Every part of the plant is poisonous, fresh or dried, and so is the water it has stood in. It is not a flower to have within reach of children or pets, and anyone cutting it should wash their hands afterward. The medicine and the poison are the same molecule at different doses, which is a good deal of why the plant has the reputation it has.