The Falkland Islands are a remote archipelago situated in the South Atlantic, some 500 km from mainland South America. The Islands experience a cool temperate oceanic climate with a mean for January and July of c. 9°C and 2°C, respectively. With ground frost a possibility throughout the year, all seasons can be experienced in a day. Contrary to popular belief rainfall is low in the Islands with a mean annual precipitation of around 585 mm. The highest point on the Islands is Mt. Usborne on East Falkland, which stands at 705 m above sea level. Soils are generally characterised by a thin, peaty surface layer, usually no deeper than 40 cm, above poorly drained, silty-clay subsoil. Mineral soils are less common but do occur where underlying rocks are exposed, such as on mountain summits and along the coast. The main vegetation types supported are acid grasslands and dwarf shrub heathland. 181 plant taxa (including one hybrid) are native to the Falkland Islands with 14 of these being found nowhere else in the world – it is these endemic plants that we seek to celebrate through this unique stamp collection.
Now considered rare, Falkland rock-cress Phlebolobium maclovianum was reported as ‘abundant on the sea coast’ by botanist Joseph Hooker when he visited the Islands in the 1800s. Hooker’s account provides evidence of a significant population reduction and there is observational evidence that grazing pressure has played a part in the decline of this crucifer as the largest known populations are found in ungrazed locations.
The charismatic Falkland Islands lady’s slipper Calceolaria fothergillii is so called because of the delicate shoe-like form of its flower’s enlarged lower lip. The intricate shape and patterning of the striking red and yellow flowers make it one of the most stunning to be seen in the Islands. This species can most frequently be found growing on coastal slopes within low-growing heathland. The white and fleshy bar folded against the outside of the lower flower lip is known to act as an edible reward to entice bird pollinators in Calceolaria fothergillii’s closest relative over in Patagonia. In the Falklands there is no record of removal of this appendage so intriguing questions remain over what pollinates C. fothergillii and whether the fleshy bar still plays a role in the process.
False-plantain Nastanthus falklandicus is one of the most range-restricted endemics found in the Falkland Islands, occurring only along the southwest coast of West Falkland and two nearby small Islands. It can be found growing in exposed, coastal sites on well-drained soils and has long taproots that make it ideally suited to such erosion-prone locations. In flower there is no mistaking N. falklandicus, as it bears a spectacular hemispherical cluster of tightly packed white flowers. It is not yet understood why this species is so limited in its distribution – just one of the many questions surrounding its ecology.
The large 3-lobed silvery leaves of the stunning silvery buttercup Hamadryas argentea make it difficult to confuse with any other plants currently growing in the wild in the Falklands. H. argentea has separate male and female plants and it has recently been noted that individual populations are often either one gender or the other. This is a worrying finding as H. argentea is classified as Near Threatened largely on the basis of its population size and this suggests that what we currently think of as ‘populations’ may just be one or two individuals that have spread vegetatively. The actual number of genetically distinct individuals across the Falklands may be drastically less than previously estimated.
Nowadays snakeplant Nassauvia serpens is found almost exclusively in stone runs and it was therefore previously thought that it had a strict requirement for this habitat. Surveys have since discovered that in the absence of grazing pressure, N. serpens can thrive in a range of other habitats close to running water or run-off.
Falkland Nassauvia Nassauvia falklandica is the most recently described vascular plant species endemic to the Falkland Islands. Known only from upland sites in two hill ranges on West Falkland, its habit makes it look similar to a dwarf version of N. serpens; its flowerheads are similarly grouped into a globular clusters at the end of stems, however it reaches only about six centimetres in height. A key feature which distinguishes this species from all other Nassauvia species is the position of its breathing holes (known as ‘stomata’) to sunken hair-filled surfaces on the undersides of otherwise hairless leaves. The hairs create a still layer of air directly above the stomata, most likely helping to reduce water loss in the windy, exposed upland sites where N. falklandica grows.
Text courtesy of Dr Rebecca Upson, Royal Botanic Gardens Kew.
Designer: Leigh-Anne Wolfaardt
Printer: BDT International Security Printing
Perforation: 14 per 2cms
Stamp size: 30.56 x 38mm
Sheetlet size: 170 x 140mm (6 x 66p)
Sheet Layout: 20 (2 x 10)
Release date: 21 November, 2016
Production Co-ordination: Creative Direction (Worldwide) Ltd