Summer has arrived but some spring flowers are still around in British Library’s St Pancras site’s Floor 3 Garden. This three-cornered garlic (Allium triquetrum L. 1753) is one of them [1,2]. It was prominent with its white flowers in May and covered half of the terrace’s wild area. Now, when its seeds are in the process of maturation, when its wilting leaves and stalks are lying on other plants and on the ground, they are less noticeable. However, they are worth finding. Something exciting is happening around the three-cornered garlic’s black seeds.
Three-cornered garlic (Allium triquetrum L. 1753), 30-45 cm, in flower on 4 May 2023, Floor 3 Garden, The British Library St Pancras, London Photo: Andrea Deri
The triangular (slightly winged) structure and rather familiar smell of garlic or leek is easy to feel when you roll the stalk of the three-cornered garlic between your fingers. Its Latin name refers to these qualities. The first name, Allium, refers to the onion genus; the second name, its species name within the genus, triquetrum, Latin for triangular in cross-section. 2 May 2023, Floor 3 Garden, The British Library St Pancras, London Photo: Andrea Deri
Three-cornered garlic covered half of the terrace’s wild area. 11 May 2023, Floor 3 Garden, The British Library St Pancras, London Photo: Andrea Deri
The wilting stalk and flowers are resting on other plants and the ground as the seeds are maturing. 25 May 2023, Floor 3 Garden, The British Library St Pancras, London Photo: Methaporn Singhanan
The white shiny oil-containing cap-like appendage on the black seed of the three-cornered garlic, called the elaiosome indicates a mutually beneficial plant-animal relationship : myrmecochory, seed dispersal by ants[4,5].
Both terms, elaiosome and myrmecochory are combinations of Greek words.
Elaiosome: oil-containing appendage on the seed that “attracts” ants.
έλαιον (elaion) - oil, oily substance
σώμα (soma) – body
Myrmecochory: seed dispersal by ants; literally: dance or movement of ants.
μυρμηξ μυρμηκος (myrmex, myrmekos) - ant, ants
χoρεια (choreia) - dance, choral dance with music and also movement of animals
Under the white petals the bulky green fruit encapsulates black seeds with white appendages. 25 May 2023, Floor 3 Garden, The British Library St Pancras, London Photo: Methaporn Singhanan
Wrapped around white petals the translucent green bulky fruit reveals the black seeds inside. 25 May 2023, Floor 3 Garden, The British Library St Pancras, London Photo: Methaporn Singhanan
Having opened the green bulky fruit one of the black seeds with shiny white appendage, the elaiosome, oil containing body, becomes visible. 25 May 2023, Floor 3 Garden, The British Library St Pancras, London Photo: Methaporn Singhanan
Attracted by the elaiosome, ants pick up it up with the seed, which together are often larger than the ants’ body, carry it to their nest, eat and feed their young ants with the nutritious oily tissue of the elaiosome, and then dump the stripped seed away from their nest.
The elaiosome (white cap on the dark seed) is about the same size as one tooth of a recycled plastic table knife in the canteen. 25 May 2023, Floor 3 Garden, The British Library St Pancras, London Photo: Methaporn Singhanan
The seed and the elaiosome together are about 3-4 mm. 25 May 2023, Floor 3 Garden, The British Library St Pancras, London Photo: Methaporn Singhanan, Andrea Deri
Title page of Rutger Sernander’s (1906) monograph on European myrmecochory. [(P) BX 80 -E(11)]
Both ants and plants benefit from this movement of seeds. Ants profit from the nutritious seasonal food source; the three-cornered garlic is getting its seeds moved to new germinating grounds.
According to a recent study over four percent of known plant species are myrmecochorous, that is, their seed dispersal is facilitated by ants. As an adaptive reproduction strategy myrmecochory appears to have evolved several times in phylogenetically unrelated plants.
Johan Rutger Sernander (1866-1944) , a Swedish botanist, published the first monograph on myrmecochory in 1906. The British Library holds a copy of this rare opus. Sernander’s comprehensive work is unique for his field experiments related to several European ant species’ preferences between various plants’ seeds and their elaiosome. The three-cornered garlic was included in the experiments and in the monograph’s splendid illustrations.
Table I Fruits and seeds with elaiosomes of various plant species. 7-8 Three-cornered garlic (Allium triquetrum) in Sernander (1906) [(P) BX 80 -E(11)]
Enlarged image: 7-8 Three-cornered garlic in Table I Fruits and seeds with elaiosomes of various plant species. Sernander (1906) [(P) BX 80 -E(11)]
Table 4 Cross-section of elaiosomes of various plant species under microscope. 135 (bottom-centre) Three-cornered garlic (Allium triquetrum). Note the large oil containing cells. Sernander (1906) [(P) BX 80 -E(11)]
While the three-cornered garlic benefits from myrmecochory it also spreads by bulbs. Furthermore, milder winters due to unfolding climatic changes also facilitate the plant’s expansion. The three-cornered garlic, native to the Mediterranean[12,13] is spreading fast towards the north[14,15]. It is now considered an invasive species in the UK and “it is an offence under Schedule 9  of the Wildlife and Countryside Act in England and Wales to plant or otherwise cause to grow this species in the wild.”
While you can’t grow this species in the wild, you can eat it as much as you like. Unlike ants that eat only the elaiosome, foraging people consume all parts, raw or cooked.
So, how did the three-cornered garlic find its home on the British Library’s Floor 3 terrace garden? This is an enigma. Certainly not by our gardeners’ intentional planting. Perhaps non-human gardeners, including ants and other animals?
Three-cornered garlic in Camley Street Natural Park, London, 11 May 2023 Photo: Andrea Deri
Having checked all other public green spaces around the British Library in St Pancras in May 2023, three-cornered garlic was not found in the neighbourhood. The nearest place where its blossom and whiff of garlic were impossible to miss was Camley Street Natural Park . Perhaps a visit to Camley Street facilitated the seed dispersal to the British Library in a bit of soil stuck to a pair of shoes or claws? Perhaps other unintentional actions? Anyway, the introduction was successful. Compared to last year (2022), significantly more three-cornered garlic flowered in the British Library Floor 3 garden this year (2023).
Illustration of the ant and the grasshopper in winter from Aesop. ‘Fab. CXXI. The Ant and the Grashopper’. In The Fables of Aesop and Others Translated into English And a Print before Each Fable by Samuel Croxall, D.D. Late Archdeacon of Hereford, The tenth edition carefully revised, and Improved., London: Printed for W. Strahan, J, [and others], 1775. pages 205–206. [Digital Store 1568/8258.]
Many generations have grown up on Aesop’s (d: 564 BC)  tale and morals about the ant and the grasshopper.
Dancing ants inspired by myrmecochory by Matthew Waters, 23 May 2023.
I am curious, what counter-stories myrmecochory could inspire about the “dancing” gourmet ants?
Written by Andrea Deri, Cataloguer, British Library
Special thanks to Matthew Waters, Manuscript Cataloguer, British Library for drawing dancing ants to illustrate this blog post and inspire counter-stories of Aesop’s classic tale, and Methaporn Singhanan, Chevening Fellow at the British Library 2022-23 for engaging in the exploration of wildlife around the British Library and sharing her photographs.
References [BL shelfmark]
All URLs accessed on 5 June 2023.
 Rose, Francis. The wild flower key: How to identify wild flowers, trees and shrubs in Britain and Ireland. Revised and Extended edition. London: Frederick Warne, 2006. pages 514-15 [YK.2007.a.20577]
 IPNI. ‘Allium Triquetrum in International Plant Name Index’, 2023. https://www.ipni.org/?q=Allium%20triquetrum
 Jones, Richard. Ants: The Ultimate Social Insects. Vol. 11. British Wildlife Collection. London: Bloomsbury Wildlife, 2022. [ELD.DS.666937]
 Morley, Wragge. Ants. Vol. 8. New Naturalist Monograph Series. London: Collins, 1953. [W.P.12018/5., W41/8118, (B) G 65 (F1)]
 Brian, M. V. Ants. The New Naturalist. London: Collins, 1977. [(B) G 61,
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[6-9] Liddell, Henry George, Robert Scott, and Henry Stuart Jones. A Greek - English Lexicon … A New Edition Revised and Augmented throughout by Sir Henry Stuart Jones [and others] Oxford: Clarendon Press, 1961. Page 527, 1749, 1154, 1998 [Open Access Humanities 1 Reading Room HLR 483]
 Lengyel, Szabolcs, Aaron D. Gove, Andrew M. Latimer, Jonathan D. Majer, and Robert R. Dunn. ‘Convergent Evolution of Seed Dispersal by Ants, and Phylogeny and Biogeography in Flowering Plants: A Global Survey’. Perspectives in Plant Ecology, Evolution and Systematics 12, no. 1 (2010): 43–55. https://doi.org/10.1016/j.ppees.2009.08.001. [6428.149200]
 Sernander, Rutger. Entwurf einer Monographie der europäischen Myrmekochoren ... Mit 11 Tafeln und 29 Textfiguren, etc. Stockholm, 1906. [(P) BX 80 -E(11)]
 Allium triquetrum L. | Plants of the World Online | Kew Science
 BSBI. ‘Definitions: Wild, Native or Alien?’, 2023. https://bsbi.org/definitions-wild-native-or-alien.
 Taylor, I., and K.J. Walker. Three-Cornered Garlic Allium Triquetrum L. in BSBI Online Plant Atlas 2020. Edited by P.A. Stroh, T.A. Humphrey, R.J. Burkmar, O.L. Pescott, D.B. Roy, and K.J. Walker. Botanical Society of Britain and Ireland (BSBI), UK Centre for Ecology and Hydrology, Biological Records Centre, 2020. https://plantatlas2020.org/atlas/2cd4p9h.ezp.
 Botany in Scotland. ‘Plant of the Week, 27th March 2023 – Three-Cornered Garlic -Allium Triquetrum’. Botany in Scotland (blog), 27 March 2023. https://botsocscot.wordpress.com/2023/03/26/plant-of-the-week-27th-march-2023-three-cornered-garlic-allium-triquetrum/.
 UK Government. ‘Wildlife and Countryside Act 1981 You Are Here: UK Public General Acts1981 c. 69SCHEDULE 9’, 1981. https://www.legislation.gov.uk/ukpga/1981/69/schedule/9.
 Wild Food UK. ‘Three-Cornered Leek’, 2023. https://www.wildfooduk.com/edible-wild-plants/three-cornered-leek/.
 Samangooei, Mina. ‘Individuals Cultivating Edible Plants on Buildings in England’. Oxford Brookes University, 2016. [EThOS DRT 800185]
 Camley Street Natural Park | London Wildlife Trust (wildlondon.org.uk)
 Aesop. ‘Fab. CXXI. The Ant and the Grashopper’. In The Fables of Aesop and Others Translated into English And a Print before Each Fable by Samuel Croxall, D.D. Late Archdeacon of Hereford, The tenth edition carefully revised, and Improved., London: Printed for W. Strahan, J, [and others], 1775. Pages 205–206. [Digital Store 1568/8258.]