Angiosperms (Flowering Plants) • Earth.com

Pincushion Plant

(Diapensia lapponica)

galery
en

Description

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 after it jumped to arctic habitat from North China and Russia. The most likely candidate for ancestor is a white-flowered D. purpurea The plants grow on exposed rocky ridges that are kept free from snow by high winds. Diapensia lapponica is extremely slow and low-growing and cannot compete with plants that overtop it. The plant is very sensitive to higher temperatures (global warming a lethal problem in Sweden) and so is often in misty foggy habitat. It usually dies when transplanted to lowland gardens 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 15 centimetres (6 in) in height, and can trap heat in the dome. It has oval blunt leathery toothless leaves, up to 1 cm (0.4 in) long, which are arranged in dense rosettes. It bears solitary white flowers (rarely pink), on stems up to 3 cm (1.2 in) 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. In places such as Newfoundland an early June and later, (often) August blooming period occurs on different plants. 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). 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 760–780 metres (2,490–2,560 ft) above sea-level. Its total extent at this site is less than 5,000 square metres (1.2 acres). A total of 1,200 clumps or mats have been counted, and monitoring since 1980 has not detected any change in this population.

Taxonomic tree:

Domain:
Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Order:Ericales
Family:Diapensiaceae
Genus:Diapensia
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