Capparis spinosa (common caper) is a large (50 to 200 cm), branched and dense thorny shrub. The branches are arched and young branches are crimson. A pair of cruel, hooked thorns are found at the base of each leaf. The leaves, and even the ends of the branches, fall in the winter. The leaves are fleshy to cartilaginous, covered by a waxy cuticle. They are round, with a small thorn at their tip. The leaves are green or tend towards crimson.
Common caper blooms for almost six months, from April until September. The flowers are single, large, non-actimorphic, very fragrant. The flower has a diameter of 6 cm. The 4 petals are arranged in 2 pairs, like a butterfly's wings. The anterior petals are separated from each other in their upper part, and the posterior ones are attached to each other as well as to the nectary at their base. They are wrinkled and somewhat wavy. The most posterior of the 4 sepals is larger than the others and concave, and is positioned opposite the posterior petals which are attached to the nectary, creating a protected reservoir for the nectar. The pollinators are different bees as well as nocturnal Sphingidae and moths. There are numerous stamens (70-120). Their filaments are white at the base and gradually turn a bright pink at their tip. The anther is pink with longitudinal veins. The ovary is carried on a long pedicel (gynophore), which is white at its base and bright pink at its tip, like the filaments of the stamens. The flower opens in the late afternoon hours, remains open for 16-18 hours, and closes on the following day at midday. It opens rapidly and its opening can be followed: first the sepals separate, then the petals gradually spread out. The stamens, that were rolled up, straighten in a fountain-like movement. The flower is revealed in all its splendor within an hour to an hour and a half. After pollination the ovary develops into a juicy fruit with a cucumber to pear shape, which is carried on a long stalk. The seeds are black, and are dispersed by birds and ants.
Common caper grows in stone walls, cliffs, stone fences, terrace walls, stone piles and poor soils, and especially in the crust of hard limestone on top of soft limestone. It is common in all areas of the Mediterranean region, and spreads even to the Judean Desert and the northern Negev. Its global distribution spreads from the countries surrounding the Mediterranean Sea and eastwards to western Asia.

Flower buds, young fruits, young branches and leaves of different species of caper are pickled and are regarded as excellent seasoning. A branch from which all organs except for one hooked thorn were removed was used for "fishing" leeches out of the throat.
The genus contains 350 species. Four species grow in Israel. The leaves are simple and entire, with hooked thorns at their base. The flower of all the species in this genus is large, with bilateral symmetry. One of the 4 sepals is larger than the others and concave. There are 4 petals, of which 2 are adjacent to this large sepal. They are attached to each other and create a reservoir for the nectar. There are numerous, long, colorful and prominent stamens. The ovary is carried on a long pedicel (gynophore), which is considered to be a primitive trait. The fruit splits longitudinally and its peel rolls backwards.

Written by Mike Livne