Diapensia lapponica
{{Short description|Species of flowering plant}}
{{speciesbox
| image = Diapensia lapponica (leaf).jpg
| image_caption = Diapensia lapponica subsp. obovata in Japan
| genus = Diapensia
| species = lapponica
| authority = L.
| subdivision_ranks = Subspecies
| subdivision =
- D. l. subsp. lapponica
- D. l. subsp. obovata
}}
Diapensia lapponica, the pincushion plant, is a plant in the family Diapensiaceae, the only circumboreal species in the genus Diapensia, the others being mainly in the Himalaya and on mountains in southwestern China. This species likely became circumboreal-circumpolar [Arctic–alpine] after it jumped to arctic habitat from North China and Russia. The most likely candidate for ancestor is a white-flowered D. purpurea(Day R.T. 2003. Diapensia on Cheju Island, South Korea and Musings on Origins. Sarracenia 11(3):29-31.) The plants grow on exposed rocky ridges that are kept free from snow by high winds.{{cite journal |author=Tiffany, W. N. |year=1972 |title=Snow cover and the Diapensia lapponica habitat in the White Mountains, New Hampshire |journal=Rhodora |volume=74 |pages=358–377}}
Diapensia lapponica is extremely slow and low-growing and cannot compete with plants that overtop it. The plant is very sensitive to higher temperatures and so is often in misty foggy habitat.(R. Day thesis) It usually dies when transplanted to lowland gardens(trials in Newfoundland, by R.Day) and so this is not recommended. Cold-treated or wild and winter-collected seed will germinate indoors. The seed and leaves are high in lipids.
It is a small cushion-forming evergreen perennial shrub, up to {{convert|15|cm|0}} in height, and can trap heat in the dome.(R. Day thesis) It has oval blunt leathery toothless leaves, up to {{convert|1|cm|1|abbr=on}} long, which are arranged in dense rosettes. It bears solitary white flowers (rarely pink), on stems up to {{convert|3|cm|1|abbr=on}} tall.
It could be aged by counting growth-rings or clump diameter, and on this basis, many Canadian plants are thought to live to over a century or two.{{cite journal |author1=Day, R. T. |author2=P. J. Scott |year=1985 |title=The biology of Diapensia lapponica in Newfoundland |journal=The Canadian Field-Naturalist |volume=98 |issue=4 |pages=425–439|doi=10.5962/p.355186 |doi-access=free }} See also the thesis by R. Day at Memorial University Newfoundland
In places such as Newfoundland two blooming periods exist on different plants: early June and (more frequently) August.Day R.T and Scott P.J. 1981. Autecological aspects of Diapensia lapponica in Newfoundland. Rhodora 83: 101-109. It is not known if this is a genetic or environmental affect. Two blooming periods are known for other plants. It often involves flower buds being formed in the present or previous year (overwintering buds).(see R. Day thesis)
Subspecies
- Diapensia lapponica subsp. lapponica in eastern North America, Greenland, Iceland, Scotland, Scandinavia, and western Arctic Russia. It forms tussocks and its leaves are oblong{{nbh}}oblanceolate to narrowly spatulate.
- Diapensia lapponica subsp. obovata in eastern Arctic Russia, Korea, Japan, Alaska and the Yukon. It forms mats because its branches can root adventitiously, and its leaf blades are obovate to spatulate{{nbh}}elliptic.
The ranges of these two subspecies do not meet in north central Canada, and possibly not in central Siberia, so they are believed to be dispersing east and west from different glacial refugia.
Etymology
The name Diapensia lapponica was given by Linnaeus to designate a flower found in Lapland ({{lang|la|Lapponia}} > {{abbr|adj.|adjective}} {{lang|la|lapponicus}}), where he traveled early in his career. Linnaeus's book about the flora of Lapland has been called "the first proto-modern flora".{{cite book|last=Frodin |first=D. G. |year=2001 |title=Guide to Standard Floras of the World: an Annotated, Geographically Arranged Systematic Bibliography of the Principal Floras, Enumerations, Checklists, and Chorological Atlases of Different Areas |edition=2nd |publisher=Cambridge University Press |isbn=978-0-521-79077-2 |chapter=The evolution of floras |chapter-url=https://books.google.com/books?id=aMjXCF4rmDUC&pg=PA27 |pages=24–51 |ref=Frodin}} However, sources disagree on how Linnaeus might have derived the genus name, Diapensia. Gray states that the term was derived from the ancient Greek name of the sanicle,{{cite book|last1=Gray|first1=Asa|title=Manual of the botany of the northern United States. Including Virginia, Kentucky, and all east of the Mississippi: arranged according to the natural system|date=1857|publisher=G. P. Putnam & Co.|location=New York, G. P. Putnam & Co.|page=332|edition=Revised|url=https://archive.org/stream/cu31924001256100#page/n363/mode/2up/search/diapensia}} a very different looking flower, and opined that the term was "of obscure meaning [and] strangely applied . . . to this boreal plant." Webster's also reflects uncertainty stating the term is "New Latin, perhaps irregular from Greek dia pente by fives + New Latin -ia; from the five-leaved calyx",{{cite web|title=Merriam Webster Online Dictionary|url=https://www.merriam-webster.com/dictionary/diapensia|website=Merriam-Webster|accessdate=10 April 2017}} a description that would apply to thousands of flowering plants. The Encyclopaedia Londinensis of John Wilkes suggested that term is from Greek,"deeply grieving or mourning; probably from its situation".{{cite book|title=Encyclopaedia Londinensis; or, Universal Dictionary of arts, Sciences, and Literature|date=1810|publisher=John Wilkes|location=London|page=799|edition=Volume V|url=https://books.google.com/books?id=GrlQUsriWScC&q=diapensia+etymology&pg=PA799}}
Status in Britain
In Britain, Diapensia is found only at a single site near Glenfinnan in Lochaber, the species' most southerly site in Europe. Here, the species occurs on acidic soil among stones on the ridge between the summit of Sgùrr an Utha and the adjoining hill called Fraoch-bheinn, at {{convert|760|-|780|m}} above sea-level. Its total extent at this site is less than {{convert|5000|m2|acre}}. A total of 1,200 clumps or mats have been counted, and monitoring since 1980 has not detected any change in this population.
The discovery of Diapensia took place in July 1951; C. F. Tebbutt, a birdwatcher, found the plant, recognising it as "something different".{{cite journal |author=Grant Roger, J. |year=1952 |title=Diapensia lapponica in Scotland |journal=Transactions of the Botanical Society of Scotland |volume=36 |pages=34–37 |doi=10.1080/13594865209441589}} Diapensia was one of a trio of Arctic plants discovered in Scotland in the early 1950s. Although no new species to Britain had been discovered in Scotland since Victorian times, in 1950, the Arctic plant Koenigia islandica had been found on the Isle of Skye, and in 1952, Artemisia norvegica was found on Cùl Mòr.{{cite book |author=Marren, Peter |year=1999 |title=Britain's Rare Flowers |publisher=Academic Press, London |isbn=0-85661-114-X}} A photograph of the plant by Robert Moyes Adam taken on 14 June 1952 (soon after the initial discovery) is held by the St Andrews University Library.{{cite web |url=http://special.st-andrews.ac.uk/saspecial/index.php?a=indexes&s=item&key=IYToxOntpOjA7czoxMToid2lsZCBwbGFudHMiO30=&pg=308 |title=Diapensia lapponica, single cushion between rocks, summit ridge between Sgurr an Utha and Fraoch-bheinn, Glenfinnan Hills |publisher=University of St Andrews |archiveurl=https://web.archive.org/web/20120205165922/http://special.st-andrews.ac.uk/saspecial/index.php?a=indexes&s=item&key=IYToxOntpOjA7czoxMToid2lsZCBwbGFudHMiO30=&pg=308 |archivedate=February 5, 2012 |url-status=dead}}
It flowers at this site in May or June, the exact time varying from year to year. Some sources state that the species is found at a second site,{{cite book |author1=Garrard, Ian |author2=David Streeter |title=The Wild flowers of the British Isles |publisher=Midsummer Books, London}}{{cite web |url=http://www.glenfinnanestate.co.uk/glenfinnan-wildlife.asp |title=Wildlife in Glenfinnan |publisher=Glenfinnan Estate}} but recent sources state that this is not the case.{{cite book |author=Wigginton, M. J. |year=1999 |title=British Red Data Books 1. Vascular Plants |edition=3rd |publisher=Joint Nature Conservation Committee, Peterborough}}{{cite book |author=Preston, C. D. |author2=D. A. Pearman |author3=T. D. Dines |name-list-style=amp|year=2002 |title=The New Atlas of the British and Irish Flora |publisher=Oxford University Press, Oxford |isbn=0-19-851067-5}}
The plant is listed in the 3rd edition of the British vascular plant Red Data Book as vulnerable. It is also protected under Schedule 8 of the Wildlife and Countryside Act 1981.