汉荭鱼腥草种

别名

纤细老鹳草（中国高等植物图鉴）

Geranium robertianum, commonly known as herb-robert or, in North America, as Robert's geranium, is a species of cranesbill that is widespread throughout the northern hemisphere and introduced to some countries in the southern. It is common in woods, hedges, gardens, and on waste ground, and can also be found on shingle beaches and limestone pavements. It is not rare or threatened and in some places it is considered to be invasive.

Description

Herb-robert is a small, usually biennial but sometimes annual or even short-lived perennial herb that typically grows to about 30 cm (1 ft) tall and broad, or sometimes up to about twice that size. Young plants have a very short vegetative stem with effectively a basal rosette of leaves on petioles 2–5 cm (0.79–1.97 in) long, while older plants put up flowering stems from the axils of one or more of these basal leaves. The flowering stems can arise vertically or sprawl along the ground, and some of them can turn into stolons by putting down roots at the nodes. The whole plant is variously hairy, with a mixture of long simple hairs and shorter gland-tipped ones.

Identification

Other cranesbills that look rather similar include shining cranesbill, which has lobed but undivided leaves, and long-stalked cranesbill, which has long points on the sepals. It is very similar in appearance to little robin but that species has smaller flowers (5–9 mm), yellow anthers, and no smell.

In Britain, in particular, it can be very difficult to separate herb-robert from little robin in coastal locations; various varieties and hybrids have been described.

Taxonomy

The scientific name was assigned by Linnaeus in Species Plantarum (1753), and it has not changed since then; but it was not original. Linnaeus cites Bauhin as having used the polynomial Geranium robertianum primum it in his Pinax theatri botanici in 1623. Bauhin, in turn, credited it to Dodoens, who listed Geranium robertianum in his Stirpium historiae in 1554. But Dodoens got the name from Ruellius who published De natura stirpium ("On the nature of species") in 1543, which was largely a translation of Dioscorides's De materia medica. In this, there is just one type of "geranion", which is described as having heads like a crane's "horn", and may have been what we now call a geranium.

Distribution and status

The main areas of distribution of herb-robert are throughout Europe northwards to the Baltic and eastwards as far as Russia. It also occurs in north Africa and it is considered also to be native in north America, although in some western states it is regarded as a weed.

It grows at altitudes from sea level to 700 m (2,300 ft) at Great Dun Fell in England and up to 2,400 m (7,900 ft) in Kashmir.

The IUCN has not assessed the threat status of this species, but in some countries it is classified as Least Concern.

Habitat and ecology

Its Ellenberg values in Britain are L=5, N=6, F=6, R=6 and S=0, which means that it typically grows in places with light shade, moist neutral soils with moderate fertility and no salinity. However, it can occupy a wide range of habitats, including shingle beaches in full sun and grikes in limestone pavements. Despite these neutral-sounding values, it is primarily a plant of woodland, and it is quite tolerant of at least moderate shade. It is also much more of a calcicole than a calcifuge, being most common in limestone and chalk woodlands, and absent from many acid habitats. The most typical vegetation communities for it in Britain include ash woods and hawthorn hedges.

Uses and in culture

White-flowered varieties of herb-robert have been cultivated in gardens for centuries. A small-flowered, fragrant white variety, 'Celtic White', is currently a popular garden plant.

Folk etymology provides several possible origins of the name of herb-robert. Some claim it is from St Rupert, who is also known as Saint Robert, because a German name for it is ruprechtskraut (another, more prosaic one is Stinkender Storchschnabel). Alternatively, a link to Saint Robert of Molesme has been proposed. Another explanation is that it could be derived from Robin Goodfellow, a hobgoblin in northern European mythology.