Above: Verbena officinalis (Common Vervain, European Vervain). The Verbenaceae (vervain family) includes certain herbs, shrubs and trees. Verbena officinalis is the principle wild species in the British Isles where it is considered either as a native or archaeophyte (ancient introduction). Often it is not easy to determine to what extent a plant was introduced into a region in ancient times and to what extent it was native.
European Vervain has a natural Eurasian distribution and is considered native to the Mediterranean where it was a popular plant to the ancient Romans who made use of it in various symbolism, in particular to signify peace (though some sources say it was sacred to the goddess Venus and so also used to symbolize marriage) and it was worn by Roman heralds. It was also associated with magic and was considered sacred to the Druids and Christians. The plant is invasive in parts of North and South America. There are also several other species of Verbena native to America, such as Verbena stricta found in prairies.
This plant is perennial, with a branched woody rootstock that puts out several stiff erect stems up to 70 cm tall, each bearing a panicle (an inflorescence with a monopodial axis with branches bearing one or more flowers) bearing simple spikes (monopodial axes bearing stalkless flowers).
The tiny flowers have 4 stamens, two shorter and 2 longer (a condition called didynamous). The corolla (5 fused petals) is pale lilac or almost white. The carpel is two-celled and splits into 4 red-brown nuts in fruit. The flowers at the base of the spikes open first with anthesis (flower opening) moving towards the apex as the flowers wither behind such that a ring of flowers moves from the base to the apex. Verbena spp. produce nectar and are chiefly insect pollinated.
The leaves of Verbena officinalis are in opposite pairs and 1 to 3 inches (2.5 to 7.5 cm) in length and pinnate (divided into leaflets on either side of a central axis, i.e. 'feather-like'). There are no stipules.
Verbena officinalis occurs in a variety of habitats including: dry banks, coastal cliffs, roadsides, waste ground and often on calcareous soils.