Plant of the week – July 27th – Teasel, Dipsacus fullonum and Dipsacus sativus

by John Grace, University of Edinburgh

Teasels are prickly herbaceous biennials, existing in wild and cultivated forms, well-known for their use in the preparation of cloth and beloved of florists. According to Stace and Crawley (2015) the first scientific record of a teasel in the British Isles was 1538. However, archaeological evidence shows that teasels were certainly here earlier than that. The wild form may even be native (Stace 2015) although its native range is generally thought to be continental Europe, Asia and northern Africa.  Teasels reached North America in the 18^th century where they are now widely distributed and considered to be an invasive weed.

The teasels belong to the Dipsacaceae, a small family represented In the British Isles by only five genera: Dipsacus (containing the teasels) and four genera of various types of scabious. Only two teasels are discussed in this article: Dipsacus fullonum and D. sativus (three others are recorded elsewhere in Britain:  laciniatus, pilosus and strigosus).

Seeds germinate in spring, forming a basal rosette of leaves and a substantial tap root. In favourable conditions the plant completes its life cycle in the following year. In poor conditions it may take longer, behaving as a ‘monocarpic perennial’. The flowering stem is vigorous, 1-2 metres tall with large more or less entire leaves that are sessile and oppositely arranged; side-branches (also flowering) are frequent. The inflorescence is like a cone, with hundreds of tiny florets over its surface, each protected by a spine. All parts of the plant bear sharp prickles. The flowers are bee-pollinated and the plant produces around 2,000 viable seeds, most of which are scattered nearby.   The plant dies after flowering ( July-August), leaving persistent dead stems complete with tough inflorescences.

In former times, extracts of teasel were important components of the medicine chest. Culpeper (1653) says the juice of the root cures wounds, cankers and fistulas, and removes warts, whilst the juice of the leaves, dropped in the ears, kills the worms in them. Distilled water from the leaves preserves the beauty of women.

However, the economic importance of teasels rests not on their medical efficacy but on their remarkable use in the process of ‘finishing’ cloth. Archaeological evidence from 13^th Century carvings in Devon and other sources (Carus-Wilson 1957, Topham 1968) show that the use of teasels for ‘fulling’ cloth has a long history and that teasels were grown in England as a cash crop from early times. It occurs also in heraldry: the 1530 Coat of Arms of the Worshipful Company of Clothworkers depicts a golden teasel head. The same process was occurring in other European countries, as the illustration of the 15th century stained-glass window shows.

In ‘fulling’, the dried inflorescences are used to ‘raise the nap’ of woven cloth by scratching the surface, thus making it appear softer and more attractive. The generic name fullonum refers to the use of the plant by the fuller, the highly skilled worker who cleanses and thickens the cloth with scratchy teasel heads mounted in a frame. This is not the same as ‘carding’, a process that comes earlier. Carding is the treatment of raw wool to align the fibres in a parallel manner, ready for spinning. In earlier times, teasels were used for both carding and napping. It is noteworthy that the Latin for thistle is carduus, hence the word ‘carding’. Perhaps teasels were considered to be thistles by the early fullers.

However, the species used for fulling is not D. fullonum but the cultivated D. sativus. Stace (2019) separates the species as follows:

Bracts on receptacle with stiff but flexible straight apical spine  D. fullonum

Bracts on receptacle with stiff, rigid, recurved apical spine          D. sativus.

The recurved spines of D. sativus are what makes it so useful for ‘raising the nap’ because they tug on the fibres. The overall appearance of the inflorescences is quite different. In D. fullonum the basal bracts (not to be confused with the receptacular bracts) curve upwards, usually equalling the top of the inflorescence, whereas in D. sativus they are more ‘patent’ i.e. stick out at right angles.

The two species are however closely related: they have the same number of chromosomes, 2n = 18, and they hybridise. There is thus an open question about whether they should be considered as one single species. In earlier floras D. fullonum is called D. sylvestris whilst fullonum is merely the cultivated variant used by fullers (Hooker  1884, Bentham and Hooker  1920). My trusty 1959 version of Clapham, Tutin and Warburg gives Wild Teasel as D. fullonum with two subspecies D fullonum ssp. sylvestris (the truly wild one) and D. fullonum ssp. fullonum (the cultivated version used by fullers). Keble Martin (1965) lists only D. fullonum, completely ignoring the cultivated species.

One wonders, which species is the one that adorns the 1530 Coat of Arms? Did the early fullers use the Wild Teasel or was the cultivated form already here, brought from the continent? The image is stylised and I’m not giving an opinion here. Readers may judge for themselves. Stace and Crawley (2015) state the first scientific record of D. sativum as 1762 but the introduction may well have been much earlier.

Today, fullonum is by far the most common of the two species, extending north into Scotland (especially on the East) but sativus is more or less southern. D. fullonum is often found in gardens and allotments where it is grown for its statuesque appearance and because it attracts small birds, particularly goldfinches. It is also found on rough ground by roads, railways, streams, woods and fields. I know a west-of-Scotland location where it grows by the coast, withstanding strong wind and salt spray. D. sativus may be more demanding: there are only four records in Scotland and elsewhere its distribution is quite sparse, perhaps reflecting the locations of former cultivation. According to Stace (2019) it is found on tips and waste ground, often from bird seed.

There appears to be rather little eco-physiological knowledge of the two species. There is however some recent work to test the hypothesis proposed by Francis Darwin (Charles Darwin’s son), that the cup-like structure formed where the leaves meet the stem collects rainwater and serves to capture and digest insects, in the manner of a true insectivorous plant. The conclusion of an experimental study was that the biomass of the plants was not affected by the feeding of dead maggots; however, this treatment did cause a 30 % increase in seed set (Shaw and Shackleton 2011).

Teasels were once cultivated on a large scale, particularly in Somerset, Essex and Yorkshire to supply the woollen mills of Yorkshire and elsewhere. The story of the industry over three centuries is well-told by Robert McMillan (https://www.teazlesandteazlemen.co.uk/) . Teasel-growing in Britain was overtaken by imported teasels and eventually teasels were replaced altogether by steel and plastic. However, there are still a few factories using teasels to raise the nap of very high-grade fabrics such as cashmere.

If your surname is Fuller or Walker then your ancestors would have known all about teasels (in Scotland the preparation of cloth was known as ‘walking’ rather than ‘fulling’). Both surnames are common, indicating the huge cultural and economic importance of this industry.

Web-sites

https://www.teazlesandteazlemen.co.uk/

http://www.hortonvillage.co.uk/teazle-farming/4594558324

Other references

Bentham G & Hooker JD (1920) Handbook of the British Flora. Reeve

Carus-Wilson E (1957) The significance of the secular sculptures in the Lane Chapel, Cullompton. Medieval Architecture 1, 104-117.

Clapham AR, Tutin TG & Warburg EF (1959) Excursion Flora of the British Isles. Cambridge.

Culpeper N (1653) Culpeper’s Complete Herbal (I used the 1995 Wordsworth Edition).

Hooker JD (1884) The Student’s Flora of the British Islands. McMillan.

Keble Martin W (1965) The Concise British Flora in Colour. Ebury Press.

Shaw PJA and Shackleton K (2011) Carnivory in the Teasel Dipsacus fullonum– the effect of experimental feeding on growth and seed set. PLoS One, 6, doi: 10.1371/journal.pone.0017935

Stace CA & Crawley MJ (2015). Alien Plants. Collins, London.

Topham PN (1968) The Fuller’s Teasel. Proceedings of the Botanical Society of the British Isles 7, 377-381.