Stachys


Stachys is one of the largest genera in the flowering plant family Lamiaceae. Estimates of the number of species in the genus vary from about 300, to about 450. The type species for the genus is Stachys sylvatica. Stachys is in the subfamily Lamioideae. Generic limits and relationships in this subfamily are poorly known.
The distribution of the genus covers Europe, Asia, Africa, Australasia and North America. Common names include hedgenettle, heal-all, self-heal, woundwort, betony, and lamb's ears. Wood betony, S. officinalis, was the most important medicinal herb to the Anglo-Saxons of early medieval England.
The Chinese artichoke, is grown for its edible tuber. Several species are cultivated as ornamentals. Woolly betony is a popular decorative garden plant.
Stachys was named by Linnaeus in Species Plantarum in 1753. The name is derived from the Greek word σταχυς, meaning "an ear of grain", and refers to the fact that the inflorescence is often a spike. The name woundwort derives from the past use of certain species in herbal medicine for the treatment of wounds.
Stachys species are used as food plants by the larvae of some Lepidoptera species, including the moths Coleophora auricella, C. lineolea, and C. wockeella, all recorded on S. officinalis. They are also widely used by the European wool carder bee, which scrape the hairs from the plant in order to use them for building their nests.

Description

Stachys is a genus of shrubs and annual or perennial herbs. The stems vary from tall, with simple, opposite, triangular leaves, long with serrate margins. In most species, the leaves are softly hairy. The flowers are long, clustered in the axils of the leaves on the upper part of the stem. The corolla is 5-lobed with the top lobe forming a 'hood', varying from white to pink, purple, red or pale yellow.

Circumscription

The distinction between Stachys and other genera is unclear and has varied from one author to another. In 2002, a molecular phylogenetic study showed that Stachys officinalis is not closely related to the rest of the genus. This study also found six other genera to be embedded within Stachys as it is currently circumscribed. The embedded genera are Prasium, Phlomidoschema, Sideritis, Haplostachys, Phyllostegia, and Stenogyne.

Fossil record

†Stachys pliocenica fossil seeds are known from Upper Miocene strata of Bulgaria and Pliocene strata of south-eastern Belarus. The fossil seeds are similar to the seeds of Stachys cretica.

Diversity

Species include: