Parnassia palustris- August 11th 2025 – Grass of Parnassus
This is an extraordinary plant with an exquisite and highly intricate flower. The structure of the plant is wonderfully captured in Jacob Sturm’s painting, and I discovered it was also a source of inspiration for the Scottish poet Andrew Lang.
Parnassia palustris by Johann Georg Sturm (Painter: Jacob Sturm), Public domain, via Wikimedia
Lang was a prolific writer in several areas – his enormous output included poetry, psychical research, anthropology, literary criticism and fairy stories. He published a collection of poems called Grass of Parnassus: first and last rhymes.
Only a few plant species excite poets, and most of them have a charismatic property: roses, daffodils, lilies, violets. They may be symbols for concepts like love and beauty, or metaphors for human emotions. We’ll return to this later, after describing the plant.
Parnassia palustris flower. Four of the five stamens have curled over to the stigmatic surface and the staminodes (glistening yellow) continue to be on display and attractive to flies. Image: Chris Jeffree.
Andrew Lang’s ‘pale star’ Parnassia palustris is a native perennial that lives in marshes, damp grasslands, dune slacks and, in Scotland, the machair: in fact, just as in line 2 of Lang’s poem “in wet green places”. In old books it is classed as a saxifrage and it is indeed quite saxifrage-like, but now it has its own Family, the Parnassiaceae1. The star-shaped ivory-coloured flowers (15-30 mm across) are held aloft on 30 cm stalks (an alternative name for the species is ‘bog-star’). Pollination is by flies, often by hoverflies, drawn to the flower by its striking appearance and smell. As well as having five stamens it has nectar-producing and sweet-smelling organs called staminodes that look like stamens but they produce no pollen and exist to attract passing flies. They have glistening knobs at the end2. The real stamens are five in number, larger, and they grow and mature at different rates, each one taking its turn to bend towards the stigma and dump its pollen, one per day. So, both cross- pollination by insects and self-pollination can occur (Ren and Bu 2014), although cross-pollination seems to be the norm.
The top flower is being visited by a ‘daddy-long-legs’ (or Crane Fly, a tipulid). Image: Chris Jeffree.
The anatomy of the plant is well-described in a research paper from Romania that you can find here. I had not realised that the flower stems are star-shaped in cross section, with thickened cells at the tips of the star for mechanical strength.
The plant thrives on a wide range of soils and does not need especially fertile conditions, although it does have a preference for calcareous substrates. It cannot tolerate shade, dry soils or heavy grazing. It must have some degree of salt tolerance as it is often found in brackish conditions, but it is not generally considered to be a halophyte. Flowering period in the UK is July to October, and reproduction is mostly by seed (little or no vegetative spread). Its British distribution has changed over the last 50 years or so, as land has been progressively drained and ‘improved’ for agricultural production. Many southern locations have been lost, but the plant is still abundant in the north.
Here, the seed capsule is developing. The seeds are tiny, dispersed by wind or water. Image: Chris Jeffree.
The name of the plant ‘Grass of Parnassus’ is curious, as this plant is nothing like a grass. The name is very old. As traced in Henry Notie’s 2017 article, it comes to us from ancient Greece via the 5-volume Greek encyclopedia of herbal medicine written by Pedanius Dioscorides known as the ‘father of herbal medicine’. He must have collected the plant from Mount Parnassus (near Athens) where it may still grow. Perhaps he called it a grass because of the grass-like markings on the petals. Gerard, in his 1597 Herbal named it Gramen parnassi but was at pains to point out that it is not a grass: ”The Grass of Parnassus hath small round leaves, very much differing from any kind of Grass”. Linnaeus made a proper botanical description of the plant in 1753 and gave us the more logical Latin name Parnassia palustris, the palustris referring to its marshy habitats. But ‘grass’ persists in the common name.
A large population of Parnassia palustris at Aberlady Bay in East Lothian, Scotland. Image: Chris Jeffree.
Returning now to the sonnet of Andrew Lang. What’s it about? The poet must have known a little about botany, perhaps from his professors at the University of St Andrews, also from wanderings in southern Scotland where he grew up. He was educated at the Loretto School and the Edinburgh Academy where in those days all students would have studied the greek language and mythology. He must have excelled: I discovered on wikipedia that he was a co-translator of Homer’s Odyssey, but I found no indication that he travelled to Greece. However, the Muse’s Hill (line 10 of the poem) is a famous hill near Athens and possibly a place where the plant would have been growing on wet patch of the lower slopes. Here is the entire sonnet:
It seems the plant is a symbol of autumn, and when the poet sees flowers it reminds him of autumns ‘long ago’. Nostalgic? Perhaps, but he has selected this plant above all others to write about, and there are plenty of alternative species which would be a more reliable signal of autumn. Possibly he thinks the flower itself looks like the face of a clock that ‘Dost keep thine hour’ (line 3) although he could not have known about the clock-like time-keeping of the stamens as described by the Chinese authors Ren and Bu (2017).
Parnassia palustris, distribution in Britain and Ireland, from BSBI/Maps. The pale squares show where it once was recorded but is there no more. These ‘empty’ squares are numerous and show up better on the original rendering of the map at https://bsbi.org/maps?taxonid=2cd4p9h.cc0
The British distribution shows how the species is often found near the coast. There is a conspicuous absence in the central belt of Scotland and the agricultural areas of the east coast. I searched the BSBI database to see whether the plant is still there ‘by the lochs of Galloway’. It is.
Notes
1The Angiosperm Phylogeny Group (2009) puts Parnassia in the larger Family of Celastraceae but Stace (2019) keeps it in the Parnassiaceae.
2Experiments described in Proctor and Yeo’s book show that small glistening objects, placed on an artificial flower, attract flies. But earlier work had concluded that the glistening knobs were ‘functionless’.
References consulted
Armbruster WS et al. (2014). In the right place at the right time: Parnassia resolves the herkogamy dilemma by accurate repositioning of stamens and stigmas. Annals of Botany, 113(1), 97-103.
Bartlett J (2017) Grass of Parnassus, Parnassia palustris.
Noltie H (2017) How the Grass of Parnassus got its name: a botanical ‘Just So’ story. https://stories.rbge.org.uk/archives/26399
Proctor M, Yeo PF (1996) The natural history of pollination. Collins, London.
Ren M-X and Bu Z-J. (2014). Is There ‘Anther-Anther Interference’ within a Flower? Evidences from One-by-One Stamen Movement in an Insect-Pollinated Plant. PloS one. 9. e86581. 10.1371/journal.pone.0086581.
Sandvik SM, and Wenche E (2009) Costs of reproduction in circumpolar Parnassia palustris L. in light of global warming. Plant Ecology 205, 1-11.
Stace CA (2019) New Flora of the British Isles, edition 4, C&A Flistics.
Sylvi MS and Totland Ø. (2003). Quantitative importance of staminodes for female reproductive success in Parnassia palustris under contrasting environmental conditions. Canadian Journal of Botany. 81, 49-56. https://doi.org/10.1139/b03-006
©John Grace
