Gagea serotina, synonym Lloydia serotina, is an Arctic–alpine flowering plant of the lily family. It is widespread across the mountainous parts of western North America, from Alaska to New Mexico, and in Europe is found in the Alps and Carpathians, as well as in Great Britain. It is also native to much of Central Asia, Siberia, China, Nepal, Mongolia, Korea and Japan.
It was originally known as mountain spiderwort, but is now known in Great Britain as the Snowdon lily, or in Welsh as brwynddail y mynydd (meaning "rush-leaves of the mountain"). In North America, it is called the common alplily.
For most of the year, the plant is visible only as long, curving, stiff, grass-like leaves, often protruding through cushions of other plants. The flowers appear from June onwards (despite the name serotina, meaning "late-flowering"), and are borne at the end of long stalks. The flowers themselves are white, with purple or reddish veins along the tepals.
In Great Britain, G. serotina is an ice age relict, only found on a few inaccessible sites in Snowdonia National Park, Cwm Idwal being one such site, and seems to have developed in isolation since the glacial period. Although the total Welsh population may number fewer than 100 bulbs, the Welsh plants are genetically distinct from other populations of the same species, and are more diverse than those found in the Alps.
While their inaccessibility protects the plants to a certain degree against grazing by sheep and trampling by hikers, they are likely to suffer under climate change, and it is believed that G. serotina will be the first plant to become extinct in Britain as a result of global warming. Plans are therefore being considered to introduce the plant to sites in Scotland, where it may survive in the longer term.
- Kew World Checklist of Selected Plant Families, Gagea serotina
- Flora of North America Vol. 26 Page 198 Lloydia serotina (Linnaeus) Salisbury ex Reichenbach, Fl. Germ. Excurs. 102. 1830.
- Biota of North America Program 2014 county distribution map
- Robin Gwyndaf (2006). The Mountain Man. A portrayal of Evan Roberts, Capel Curig, rockman, botanist and conservationist. Capel Curig: Friends of St. Julitta's Church. ISBN 0-9552995-0-0.
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- Linnaeus, Carl von. 1753. Species Plantarum 1: 294, as Bulbocodium serotinum .
- Heinrich Gottlieb Ludwig Reichenbach. 1830. Flora Germanica Excursoria 102, as Lloydia serotina
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- Paul Brown (March 27, 2003). "Global warming threatens Snowdonian plant". Guardian Unlimited.
- T. G. Tutin, V. H. Heywood, N. A. Burges, D. M. Moore, D. H. Valentine, S. M. Walters & D. A. Webb, eds. (1980). Flora Europaea 5. Cambridge University Press. p. 25. ISBN 978-0-521-20108-7.
- "Lloydia". World Checklist of Selected Plant Families. Royal Botanic Gardens, Kew. Retrieved 2014-01-09.
- Flora of China Vol. 24 Page 122 洼瓣花 wa ban hua Lloydia serotina (Linnaeus) Reichenbach, Fl. Germ. Excurs. 102. 1830.