Torilis japonica (Houtt.) DC., Upright Hedge-parsley

Account Summary

Growth form and preferred habitats

This is an erect, semi-rosette, hairy, winter annual that rarely or occasionally behaves as a biennial. It grows on solid, striate stems 5-125 cm tall, pale green, sometimes tinted purple, clad with closely appressed deflexed bristles. The plant has a slender tap-root (up to 8 mm thick) and produces much divided, 1- to 3-pinnate, fern-like, hairy leaves on slender petioles that are also covered with deflexed appressed bristles (Tutin 1980; Grime et al. 1988, 2007; Sell & Murrell 2009; Jonsell & Karlsson 2010).

T. japonica appears on dry banks on woodland margins and clearings, in rough grass along roadside verges and hedgerows, and on dry stony banks, rocks and cliffs in a wide variety of other mainly limestone or base-rich, somewhat disturbed habitats. The soils it prefers are dry to moderately dry and fertile, mildly acid to neutral in reaction. However, it prefers situations where vigorous growth of competing species is limited by periodic drought, instability of steep terrain, or some other negative environmental factor(s). T. japonica prefers full sun but can tolerate moderate shade. Many, but not all, of the wide range of habitats the species occupies are artificial, wayside, or 'man-made', such as quarries and roadside banks and verges and it tends to be confined to lowland areas, below 400 m (Grime et al. 1988, 2007; New Atlas).

Upright Hedge-parsley is capable of growing to its maximum height (c 125 cm) if it finds deeper pockets of suitable soil and some form of support to climb. However, very often it is much less tall than this, depending upon a combination of the severity of the growing conditions and particularly upon the density and height of its competitors. Its competitors often include established, deeper rooted, perennial species, with which it is unusual for an annual ruderal to manage co-habitation. The fact that it can grow in more open areas in woods or on their margins, in hedgerows and in tall verge grasslands that are not cut or only annually mown, proves that T. japonica is able to compete and persist among mainly perennial companions. The commonest associates in the Sheffield area of England were Dactylis glomerata (Cock's-foot), Festuca rubra (Red Fescue) and Arrhenatherum elatius (False Oat-grass).

T. japonica is generally absent from regularly cut grassland and from well-managed pastures. The established strategy of the species is classified as intermediate between C-S-R (ie a balance of Competitor, Stress tolerator and Ruderal) and Competitive Ruderal (Grime et al. 1988, 2007).

Fermanagh occurrence

While T. japonica is quite frequently found in Fermanagh and is widely scattered, having been recorded in 94 tetrads (17.8%), in most situations it is only sparsely present. Eight tetrads have pre-1976 records only. Occasionally, however, it is locally abundant along roadsides. In the absence of Chaerophyllum temulum (Rough Chervil) in Co Fermanagh, this bristly hairy, rather tall winter or spring annual is the last of the three most common wayside umbellifers in B & I to flower in the VC.

Flowering reproduction

The compound, flat umbels 2-4 cm across of pinkish- or purplish-white, distinctly radiate (zygomorphic) flowers make their appearance from July onwards. Fruiting begins in early September, following insect- or self-pollination and fertilization and the 'seed' (ie mericarp fruits) are retained on the plant as it dies off (Fitter 1987; Jonsell & Karlsson 2010). In a mild season, however, late flowering plants can still be seen well into the autumn and the dead stems with their characteristic spine covered, oval fruits are still perfectly identifiable in January (Tutin 1980). The fruits in this family are single-seeded mericarps formed in pairs, separating and hanging apart when fully mature and ready for dispersal (S.L. Jury, pers. comm., March 2005).

Compared with the seeds of most other annual species of similar habitats, the 'seeds' (ie fruit mericarps) of T. japonica are large, measuring 3-4 mm long. Relatively long bristles or spines (0.4-0.5 mm long) cover the mericarps, and they are all curved at their tip (but not hooked), which enables them to be transported by attachment to the coats of passing animals. When there is no animal contact, 'seed' dispersal would appear to be severely limited. Some populations of T. japonica have fruits with the mericarp spines reduced to small tubercules; it has been suggested that these fruits serve to maintain the local population, while the spiny ones travel further and colonise new areas (Jury 1980).

Seeds germinate mainly in the autumn and the plantlets overwinter as small leaf rosettes with a slender taproot (Grime et al. 1988, 2007). Alternatively, some seed overwinters and germinates in the following spring after a chilling requirement has been met. Naturally enough, the resultant plants mature and fruit later in the season. There are conflicting reports of the longevity of seed in the soil bank, estimates varying from transient to long-term persistent for over five years (Grime et al. 1988, 2007; Thompson et al. 1997).

British and Irish occurrence

Of the three most common roadside umbellifers in B & I, the hectad maps in the New Altas demonstrate T. japonica is the least widespread. In comparison with the other two, it is slightly less well represented than Anthriscus sylvestris (Cow Parsley) and more so than Heracleum sphondylium (Hogweed), especially in N & W Ireland, and much less so on the predominantly wet, acid, peaty soils of N & W Scotland (Preston et al. 2002).

European and world occurrence

T. japonica is widespread throughout temperate Europe from Ireland eastwards to W Russia and southwards just into N Africa. It extends in an extremely scattered, disjunct manner across to Japan, as its name suggests, where it has a secondary, and very much more minor, centre of distribution. The species is a quite widely scattered alien introduction in N America, especially in eastern states of the US (Hultén & Fries 1986, Map 1433). T. japonica is regarded as an invasive species in southern parts of Canada and in the Mid-western, Eastern, Southern parts of the US, including Oregon.

Uses

T. japonica does not feature at all in western herbal medicine (Grieve 1931; Allen & Hatfield 2004), but it has a long history going back centuries in traditional Chinese medicine. The plant contains a range of bioactive ingredients that give it antiviral, antibacterial, anti-inflammatory and anti-oxidative properties. It is used today in the treatment of Lyme disease, influenza and a number of other inflammatory conditions.

T. japonica may also have potential to fight several cancers through a terpene it produces called Torilin that is extracted from its fruits. This compound has been shown to inhibit the growth of blood vessels in tumour development from benign to malignant and thus has a toxic effect on tumours. It also has been found to inhibit the conversion of testosterone to androgen, which is being studied further in the treatment of both prostate cancer and alopecia.

Names

The genus name 'Torilis' is an example of a pure label invented or dreamt up by the 18th century French taxonomist Michel Adanson (1727-1806), that in common with other names he provided (eg Apera, Cicendia, Kalanchoe and Tolpis) is meaningless and has no translation leading to or alluding to anything else (Gilbert-Carter 1964). As such, and with this knowledge, the current author (RSF) finds the label name surprisingly refreshing! The Latin specific epithet 'japonica' means 'of Japan', but this is misleading and inaccurate, since the plant has a widespread range right across the whole of Eurasia and Japan is merely a secondary centre of distribution, rather than a genuine point of species origin.

The English common name 'Upright Hedge-parsley' is a typical book name. Grigson (1955, 1987) lists a total of ten additional common names, several of which allude to the lace-like, heavily dissected leaves and white flower heads, eg 'Honiton Lace', 'Lace Flower', 'Lady's Lace' and 'Lady's Needlework'. These names, and several other English common names, are shared with Anthriscus sylvestris (Cow Parsley), as Grigson says, "the companion plant of white lace along the roads, though Torilis japonica blossoms as the true Cow Parsley fades. It is the roadside lace of high summer."

Threats

None.

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