Cudweeds are grey-looking herbs with yellowish flowers, belonging to the Asteraceae (daisy) Family. There are over 50 species in the world. This one, the Jersey Cudweed Gnaphalium luteoalbum, is a rare plant over much of Britain.
Gnaphalium luteoalbum, also known as Laphangium luteoalbum, showing the general structure of the plant. Image: Chris Jeffree.
It was first recorded by William Sherard in Jersey, 1869, “on the walls and dry banks, very common”. Its first sighting on mainland Britain was 1802 (Cambridgeshire). Then came a few records from Norfolk. When Gurney (2004) wrote about its appearance at a bird reserve in Dungeness, Kent the plant was considered ‘critically endangered’. Now it is spreading in the south of England and it has recently turned up in several new locations in Scotland, mostly around Edinburgh (Warriston, the Royal Botanic Garden, Granton, Canonmills, Newhaven).
British distribution of Gnaphalium luteoalbum, from BSBI/Maps.
The earliest Scottish records were made by Ida M Hayward at the border town of Galashiels in 1908 and 1914. She was a self-taught botanist, inspired by the rare plants that turned up at her uncle’s woollen mill, often growing along the banks of the River Tweed. Many of these species were accidentally introduced as seeds, tangled in the raw wool coming from distant lands, including Australia and South Africa.
This is the (facsimile) cover of Hayward’s book published in 1919. She was assisted by a well-established botanist, GC Druce, who was able to identify the many alien species that were found in and around Galashiels. Ida Hayward became a Fellow of the Linnean Society in 1910 and the Botanical Society of Edinburgh in 1913. There is a box representing her archive at the Royal Botanic Garden, Edinburgh.
But Gnaphalium luteoalbum may not have travelled half-way around the world like many of her plants. More likely, it came from Jersey which was another centre for the manufacture of woollens (eg the classic ‘Jersey’). Merchants and woollen fabrics must have frequently travelled between these locations with at least a few viable seeds.
The Kew database says it is native to Britain, and Pearman (2017) included it in his book on the discovery of native plants. But opinion has shifted somewhat. Stace is cautious in the 4th edition of his Flora, saying ‘possibly native’ and in the BSBI Atlas 2020 it is mapped as an alien.
Green areas show countries where the plant is considered native and purple are the places where the species has been introduced. From Plants of the World Online. Unfortunately this map doesn’t show New Zealand, where the species is also considerd to be native.
The Atlas describes its habitat as follows: “waste places, including pavements, gravel drives, railway sidings, china clay waste, tracks and refuse tips. It is thought to have a long-lived, persistent seed bank”. The PLANTATT data base suggests it is a plant that can tolerate very low nitrogen status but cannot tolerate shade. Perhaps it will spread further, as appropriate conditions are not rare; but it will not be able to compete very well with other species. I shall make a special effort to look for it in derelict sites next year.
Global distribution according to GBIF. The lower image shows the European pattern more clearly.
John Gerard’s 1597 Herbal illustrates 13 species of Gnaphalium, but luteoalbum is not among these. Stace’s first edition of the New Flora of the British Isles (1991) has seven species; however, by the 4th edition of the book there is only one because taxonomic revision has shifted the rest to other genera. Our species Gnaphalium luteoalbum has now become Laphangium luteoalbum. But I suspect it will be known by its old name for many years.
Gerard refers to the medicinal uses of Gnaphalium (not refering to any particular species). He lists the virtues:
The plant contains many biologically active compounds, with anti-fungal, anti-bacterial, anti-oxidative and cyto-toxic constituents. There is modern work on the subject, quite specific to G. luteoalbum (Al-Snafi 2019):
G. luteoalbum came to my attention just a few days ago when it was mentioned in a short Guardian article here. The article reports the appearance in Britain of a rare butterfly called the American painted lady whose larvae may feed on Jersey Cudweed. However, my brief look into this newspaper story suggests it may feed on many other plants (but in USA it sometimes feeds on Gnaphalium obtusifolium).
G. luteoalbum plants in various settings. Stems are up to 50 cm tall, and the upper sides of the leaves are particularly ‘wooly’ . Images: left and right, Richard Milne; centre, Sue Jury.
The images above demonstrate the ‘felted’ appearance of the leaf, caused by matted trichomes that secrete surface flavonols (including one called gnaphaliin) which give the leaf surfaces its ‘wooly’ appearance. These compounds are formed in response to ultra-violet radiation (UV-B); Cuadra et al (1997) showed that G. luteoalbum produces differing amounts according to the amount of UV-B during development, providing an effective sun-screen to prevent UV damage to DNA.
Finally, you may have wonderd about pronunciation of Gnaphalium. The ‘G’ is silent like gnash, gnu, gnarl, gnat and gnome.
References
Al-Snafi AE (2019) The medical benefits of Gnaphalium luteo-album L. Journal of Pharmacy 9, 40-44.
Cuadra P et al. (1997) Increases in surface flavonols and photosynthetic pigments in Gnaphalium luteo-album in response to UV-B radiation Phytochemistry 45, 1377-1383.
Gurney M (2004) Jersey Cudweed at Dungeness RSPB Reserve, East Kent. Watsonia 25, 107-113.
Pearman DA (2007) Far from any house’ – assessing the status of doubtfully native species in the flora of the British Isles. Watsonia 26, 271-290.
Stace CA (1991) New Flora of the British Isles. (1st Edition). Cambridge.
Stace CA (2019) New Flora of the British Isles. (4th Edition). C&A Floristics.
©John Grace
Botany in Scotland 