… the plant, viewable locally in planters outside two office buildings, one a block north and one a block west of where I live. They thrive there; they are tough plants, aggressive even — they are invasive pest plants in South Africa and Australia — though they suffer some from vandals who manage to break their stems off. The local species, Equisetum hyemale, in a big stand:
On the genus, from Wikipedia:
Equisetum ([main accent on the second syllable] … horsetail, snake grass, puzzlegrass) is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.
Equisetum is a “living fossil” as it is the only living genus of the entire class Equisetopsida, which for over one hundred million years was much more diverse and dominated the understory of late Paleozoic forests. Some Equisetopsida were large trees reaching to 30 meters tall. The genus Calamites of the family Calamitaceae, for example, is abundant in coal deposits from the Carboniferous period.
… The pattern of spacing of nodes in horsetails, wherein those toward the apex of the shoot are increasingly close together, inspired John Napier to discover logarithms.
… The name “horsetail”, often used for the entire group, arose because the branched species somewhat resemble a horse’s tail. Similarly, the scientific name Equisetum derives from the Latin equus (“horse”) + seta (“bristle”).
Other names include candock for branching individuals, and snake grass or scouring-rush for unbranched or sparsely branched individuals. The latter name refers to the rush-like appearance of the plants, and to the fact that the stems are coated with abrasive silicates, making them useful for scouring (cleaning) metal items such as cooking pots or drinking mugs, particularly those made of tin.
At least three cool things here: the “living fossil” thing; and then from it, the genus being the only surviving one in its plant family (and in fact its entire class), which makes the Equisetaceae #60 in the continuing inventory of plant families on this blog; and the silicate coating, which makes the plants resistant to injury as well as useful in the kitchen.
And on the particular species, again from Wikipedia:
Equisetum hyemale [Latin hiemāle ‘winter’ (neut.sg.) … is a perennial herb in the fern Division Pteridophyta. It is a native plant throughout the Holarctic Kingdom, found in North America, Europe, and northern Asia.
… Equisetum hyemale is cultivated as an ornamental plant, for use in contained garden beds and planters, and in pots. It is a popular “icon plant” in contemporary Modernist and Asian style garden design. Its tight verticality fits into narrow planting spaces between walkways and walls, and on small balconies.
It is also used as an accent plant in garden ponds and ornamental pools, and other landscape water features, planted in submerged pots.
… The plant spreads very aggressively by underground runners, reaching under/past pavements and garden walls. Root barriers or large sunken planters ease containment in the garden.