Last weekend we had a family walk at the village of Blackness, in West Lothian. Its claim to fame is ‘the ship that never sailed’. The ‘ship’ is a castle, built on the edge of the Forth estuary in the 15th Century. It has a pointed end that resembles a warship, and it may have deterred enemies at various times over the centuries. Immediately, I spotted some unusual plants growing along the beach, between the footpath and the stranded seaweeds. It looked like an Orache (Atriplex) but the leaves seemed too narrow and I was puzzled.
Atriplex littoralis, the Grass-leaved Orache, between path and shore at Blackness, West Lothian. Photo: John Grace.
Like most people, I’ve always struggled to identify the Oraches (Atriplex) and the related Goosefoots (Chenopodium). Neither have petals, and both have a ‘mealy’ look, but Oraches have a more complicated floral structure with male and female flowers on the same plant. The female flowers of Oraches are protected by a purse-like pair of bracts which become enlarged as the seeds develop and they provide reliable diagnostic features for identification (see Taschereau 1985 or Stace 2019). From the crowded bracts, I was fairly sure this one was an Orache. I took a few photographs, and on my mobile phone I called up my new friend PlantNet. It thought the most likely species was Atriplex littoralis, the Grass-leaved Orache.
Many branches on each stem, becoming entangled. Photo: John Grace.
Back home I flicked through the pages of Taschereau (1985) and Stace (2017) and then I stumbled upon an excellent article from the Hampshire Flora Group, with tiny but well-drawn sketches. My plant turned out indeed to be the Grass-leaved Orache (PlantNet was right). I confirmed this by consulting the on-line herbarium. I found one specimen from 1924 by the well-known botanist Job Edward Lousley that looked just like ‘my’ plants.
I consulted the data base of the BSBI to see whether the species had been seen here by others. There were several records by J. Muscott but none more recent than 2007.
The genus Atriplex belongs to the plant Family Amaranthaceae, which contains familiar garden plants such as Amaranthus, Beetroot and Spinach as well as well-known ‘weeds’ Chenopodium album (Fat Hen) and Blitum bonus-henricus (Good-King-Henry). Many of its members are halophtes (i.e. salt-tolerant), such as Salicornia (Marsh Samphire) and Atriplex (called Saltbush in north America). Remarkably, some members have the photosynthetic pathway known as C4.
Atriplex littoralis, the Grass-leaved Orache, is a native biennial plant occurring on the sea-shore, usually rooted in sand. In the British Isles it is more abundant on the eastern shores but since the early 1980s it has spread rapidly inland along salt-treated roadsides, particularly in eastern England (Stroh et al. 2020).
Detail of one of the shoots, showing the grass-like leaves associated with flower clusters. Image: John Grace.
In Scotland, it is not very common, though there is an unexplained dense cluster in the Northeast, around Inverness. Could it be that botanical recorders there have been more vigilant? Its occurrence along major roads in SE England is interesting, and now a few of the Scottish records are also well inland and near to major roads. I expect it will spread further on the tyres of motor vehicles.
Left, flower clusters in the axils of leaves; right, developing fruit. Note the mealiness, and the spikes on the pair of fleshy bracts which will open like a purse when ripened. Photos: John Grace.
Lacking petals and often looking storm-battered, these plants are not beauties! Oraches are especially ‘mealy’ giving them an overall grey appearance. The mealy substance on the surface of many of the Amaranthaceae is from the plant hairs (trichomes) that bear ‘salt bladders’ and store excess salt. The bladders eventually burst and collapse leaving waxy debris behind. This debris may have additional value in deterring insects and filtering UV-radiation.
Atriplex littoralis. Left: distribution of records up to 1987; right: all records up to the present. From BSBI/Maps.
Flowering occurs in July and August but now (October) the plants are setting seed. I found the Blackness plants only last week, too late to record the flowers so my images show the only the developing fruits with their fleshy bracts that can be teased apart to show the ovule. This full-blown account of the reproductive biology of A. littoralis is taken from Taschereau (1985):
Few botanists and few journals publish such thorough accounts of plants any more. Pierre Michel Taschereau appears to be working in Canada now, and has published a similar account of Atriplex found in Nova Scotia. He has also described hybridisation within the genus Atriplex (Taschereau 1986). For Britain and Europe, Stace (2019) lists 12 pure species of Atriplex and several hybrids. The hybrids involving A. littoralis are with A. prostrata, A. longipes, and A. patula.
I walked from Blackness along a cycle path towards Bo’ness, to see what other species may be present. I was not disappointed. I came to a section of the beach which was strangely depressed, and growing there I found Salicornia and Suaeda maritima, both halophytes belonging to the Amaranthaceae. Were these new records for Blackness? No, both had been recorded long ago by the BSBI recorder J. Muscott. Nevertheless, I had enjoyed my walk.
Salicornia growing 1 km east of Blackness; only a small population in a depressed area of beach that might have been a lagoon. The small area is bestrewn with oyster shells and also has Suaeda maritima (Seablite) and Triglochin maritima (Sea Arrow Grass). For news of Oysters see here. Photo: John Grace.
References
Stace CA (2019) New Flora of the British Isles. C&M Floristics.
Stroh PA et al (2020) BSBI Online Plant Atlas
Taschereau PM (1985) Taxonomy of Atriplex species indigenous to the British Isles Watsonia, 15, 183-209
Taschereau PM (1986) Hybridization in the genus Atriplex section Teutliopsis (Chenopodiaceae) Watsonia, 16, 153-162
Other useful sources
http://webidguides.com/_templates/group_oraches.html#Babington’s%20Orache
Botany in Scotland 