Harmel

Habitat

It grows in dry areas in the United States. It can be considered a halophyte.

In Kashmir and Ladakh it is known from elevations of 300–2400 m, in China 400–3600 m, in Turkey 0–1500 m, and in Spain 0–1200 m.

In China it grows in slightly saline sands near oases and dry grasslands in desert areas.

In Spain it can be found in abandoned fields, rubbish tips, stony slopes, along the verges of roads, ploughed and worked earth, as well as in disturbed, saline scrubland.

In Morocco it is said to grow in steppes, arid coasts, dry uncultivated fields and amongst ruins. A study in Morocco found that it could be used as an indicator species for rangeland degraded from agricultural activities, when found in association with certain "Artemisia" sp., "Noaea mucronata" and "Anabasis aphylla". In Israel it is a common dominant plant along with "Anabasis syriaca" and "Haloxylon scoparium" in a low semi-shrubby steppe ecosystem which during dry years is almost devoid of plant cover, growing on saline, loess-derived soils. In rainy times "Leontice leontopetalum" and "Ixiolirion tataricum" appear here. It also grows in Israel in semi-steppe shrublands, Mediterranean woodlands and shrublands, and deserts. Between 800–1300m elevation on the sandstone slopes of the mountains around Petra, Jordan, there is an open Mediterranean steppe forest dominated by "Juniperus phoenicea" and "Artemisia herba-alba" together with occasional trees of "Pistacia atlantica" and "Crataegus aronia" with common shrubs being "Thymelaea hirsuta", "Ephedra campylopoda", "Ononis natrix", "Hammada salicornia" and "Anabasis articulata"; when this habitat is further degraded by overgrazing "P. harmala" along with "Noaea mucronata" invade. It is often found with "Euphorbia virgata" in the foothills of Mount Ararat, Iğdır Province, Turkey.

The flowers are pollinated by insects. Little is known about pollen vectors. A year-long study around the town of St. Katherine in the El-Tur mountains of southern Sinai found "P. harmala" to be exclusively pollinated by the domesticated honey bee, "Apis mellifera", although it is possible these animals are displacing native bees. The floral morphology, nectar amount and composition – high in hexane sugars, presence of toxic alkaloids and high proline content together suggest pollination by short-tongued bees.

Regarding seed dispersal it is considered a barochore. According to a Mongolian study, its seeds are exclusively dispersed by human activities, although "Peganum multisectum", sometimes seen as a variety or synonym of this species, is dispersed solely by water flow.

A species of tiny, hairy beetle, "Thamnurgus pegani", has been found inhabiting stems of "P. harmala" in Turkey and elsewhere. It feeds only on "P. harmala". When the aerial parts of the plant begin to die off in the autumn, the adult beetles retreat to overwinter in the soil underneath the root-crown, or in old larval tunnels in the dead stems; emerging in the spring, the females bore small holes in the now shooting stems of the plant, in which they lay their eggs. The hatched larvae bore inward toward the pith. The beetles somehow infect the surrounding tissue in the tunnels with a fungus, "Fusarium oxysporum". The infected plant tissue turns blackish and is then used by the adult beetles and their larvae as a food source, until they are ready to pupate within the stem tunnels. It has been proposed as a candidate for using in biological control of "P. harmala", as a relative of it, "T. euphorbiae", has been approved for use against invasive "Euphorbia" in the United States.

Evolution

As the plant is popular in Persian cultural traditions, and is a hallucinogen, the linguists David Flattery and Martin Schwartz wrote a book in 1989 in which they theorised that the plant is the Avestan "haoma" mentioned in Zoroastrianism. The transcribed word "haoma" is thought to be likely related to the Vedic word "soma"; these names refer to a magical, purportedly entheogenic plant/drink that is mentioned in ancient Indo-Iranian texts but whose exact identity has been lost to history.

This plant was first described in a recognisable manner under the name by Dioscorides, who mentions it is called μῶλυ in parts of Anatolia. Galen later describes the plant under the name, following Dioscorides by mentioning numerous other names it was known by:,, and in Syria,. For much of the subsequent history of Europe Galen was seen as the pinnacle of human medical knowledge. As such, during the early Middle Ages, the herb was known as "moly" or.

The 12th century Arab agriculturist Ibn al-'Awwam from Seville, Spain, wrote that the seeds were used in the baking of bread; the fumes being used to facilitate fermentation and help with the taste.

By the mid-16th century Dodoens relates how apothecaries sold the plant under the name "harmel" as a type of extra-strength rue.