In architecture, an opening or a panel dividing by cusps or foliations into four leaves, or more correctly the leaf-shaped figure formed by the cusps. It is an ornament which has been supposed to represents the four leaves of a cruciform flower, and is common in the tracery of Gothic windows.

Quatrefoil Architecture

In architecture, an opening or a panel dividing by cusps or foliations into four leaves, or more correctly…

An illustration of white clover (left) and red clover (right). Clover (Trifolium), or trefoil, is a genus of about 300 species of plants in the pea family Fabaceae. The genus has a cosmopolitan distribution; the highest diversity is found in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes on mountains in the tropics. They are small annual, biennial, or short-lived perennial herbaceous plants. The leaves are trifoliate (rarely 5- or 7-foliate), with stipules adnate to the leaf-stalk, and heads or dense spikes of small red, purple, white, or yellow flowers; the small, few-seeded pods are enclosed in the calyx

Clover

An illustration of white clover (left) and red clover (right). Clover (Trifolium), or trefoil, is a…

Illustrated is the root system of trifolium pratense, a variety of clover.

Clover Root System

Illustrated is the root system of trifolium pratense, a variety of clover.

Crimson clover is the common name of trifolium incarnatum. It is an annual from southern Europe.

Crimson Clover

Crimson clover is the common name of trifolium incarnatum. It is an annual from southern Europe.

A healthy potted clover plant.

Clover, potted

A healthy potted clover plant.

A potted clover plant, stunted as a result of a nitrogen deficiancy in the soil.

Potted and stunted clover

A potted clover plant, stunted as a result of a nitrogen deficiancy in the soil.

A red clover plant. It does not reproduce except from seed.

Clover, red

A red clover plant. It does not reproduce except from seed.

Branch of white clover showing the method of forming new plants.

White clover

Branch of white clover showing the method of forming new plants.

A white clover plant grown from a single seed, showing spreading habit.

White clover

A white clover plant grown from a single seed, showing spreading habit.

Crimson Clover (Trifolium incarnatum).

Crimson Clover

Crimson Clover (Trifolium incarnatum).

A genus of parasitic plants, natural order Concolvulaceae. Dodder.

Cuscuta

A genus of parasitic plants, natural order Concolvulaceae. Dodder.

A horseshoe covered in clovers.

Horseshoe Doodad

A horseshoe covered in clovers.

"A genus of clover-like plants of the natural order Leguminosae, with ternate leaves, differing from the clovers in the generally elongated racemes o flowers, the stamens not adhering to the corolla, and the 1-3 seeded tumid pods. All species have a strong peculiar sweetish smell, which becomes more agreeable when they are dried, and is owing to the presence of Coumarin." — Chambers, 1881

Melilot

"A genus of clover-like plants of the natural order Leguminosae, with ternate leaves, differing from…

Red clover (Trifolium pratense).

Red Clover

Red clover (Trifolium pratense).

Illustrated is the penetrating root of red clover. It is a fifteen month old plant that grew in hard clay soil.

Red Clover Root

Illustrated is the penetrating root of red clover. It is a fifteen month old plant that grew in hard…

Of the sorrel family (Oxalidaceae), Oxalis filipes.

O. Filipes

Of the sorrel family (Oxalidaceae), Oxalis filipes.

Of the sorrel family (Oxalidaceae), Oxalis grandis.

O. Grandis

Of the sorrel family (Oxalidaceae), Oxalis grandis.

Of the sorrel family (Oxalidaceae), Oxalis repens.

O. Repens

Of the sorrel family (Oxalidaceae), Oxalis repens.

White clover (Trifolium repens).

White Clover

White clover (Trifolium repens).