Origin and Habitat: Pelargonium cotyledonisSN|32394]]SN|32394]] is endemic to the island of Saint Helena in the South Atlantic Ocean. It occurs in the south west of the island and was recorded from several localities in 1875; several thriving plants were still found in 1970 but nevertheless the population is drastically low
Altitude range: 150-300 metres above sea level.
Habitat and ecology: Pelargonium cotyledonisSN|32394]]SN|32394]] it is the sole species of Pelargonium the island of Saint Helena. It is now confined to the south and south-west coast on barren and exposed rocky cliffs, overhanging the sea on the windward side of the island and more or less inaccessible to introduced livestock. This area of rocky desert and cliff has a rainfall of only 150-380 mm per year. P. cotyledonis has the ability to retain vitality for months without either soil or water. This species is in danger of extinction, its decline was caused by the introduction of goats in 1513 which formed herds nearly 2 as long within 75 years. They devastated the forests originally covering the island . In recent years the goats have been effectively controlled and few if any survive today.

• Pelargonium cotyledonis (L.) L'Hér.
• Geranium cotyledonis

Description: Pelargonium cotyledonisSN|32394]]SN|32394]], (local name old father live forever) is a perennial sparsely branched succulent, for most of the year a thick and contorted, leafless, shrublets, 3-15 cm thick, up to 30 cm high, but occasionally as tall as 1 m, producing in about May or June a loose rosette of orbicular leaves 2-5 cm long on stalks up to c. 8 cm long. The five petals are pure white, equal in size, and evenly arranged round the centre of the flower to lend it a perfectly regular appearance. Pelargonium cotyledonisSN|32394]]SN|32394]] is a truly odd species in a genus remarkable for its diversity, and the most curious member of the endemic flora of Saint Helena. The leathery, prominently-veined leaves and the regular, pure white flowers distinguish this species from all others. In the genus it is the only species with pure white petals without any coloured markings.
Stems: Rough due to the subpersistent stipules and scaly bark, branched, succulent to somewhat woody, to 5 cm in diameter, tips pubescent greyish-green but soon becoming greyish-brown to brown.
Leaves: Deciduous in summer, clustered and closely-spaced near branches tips, simple. Petioles up to 2.5-8 cm long (usually longer than lamina) attached towards the centre of the underside (peltate) and villous. Blades, leathery, wrinkled, conspicuously veined, more or less orbicular to cordate,(20-) 30-40 (-50) mm long and wide, glabrous or minutely hairy above, discolorous, normally green turning reddish later, paler and densely woolly below . Base cordate, apex obtuse, margin crenate and slightly rolled down. Stipules narrowly triangular, pointed, 3-5 mm long, 1-2 mm broad, pubescent.
Inflorescences. In the centre of the rosette is borne a slender scape 20 cm or more high, bearing loose branched umbels of flowers. Part-inflorescences with 5-15 floweres, each with 5 white spreading obovate petals 10-14 mm long. Peduncles 30-60 mm long, with glandular hairs. Pedicels 4- 8 mm long with glandular hairs. Hypanthium 0.5-1.5 mm long, conspicuously thickened basally. Sepals lanceolate, green, 6 mm long, 2 mm broad, hairy. Petals 5, white, or sometimes with a pale pink flush, equal in size and shape, elliptic to slightly obovate with short claws, 12-15 mm long, 5-7 mm wide. Stamens 5 (4 long, 1 short); pollen white.
Fruits (mericarps): Linear, ribbed, base of mericarp approx 4 mm long, tail 10-15 mm long, emerging from the small cup of the persistent sepals.

Bibliography: Major references and further lectures
1) Eggli, U., ed. “Illustrated handbook of succulent plants: Dicotyledons”. 2002
2) Wikipedia contributors. "Pelargonium cotyledonis." Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 25 June 2015. Web. 18 Jan. 2016.
3) Klaus Kubitzki “Flowering Plants. Eudicots: Berberidopsidales, Buxales, Crossosomatales, Fabales p.p., Geraniales, Gunnerales, Myrtales p.p., Proteales, Saxifragales, Vitales, Zygophyllales, Clusiaceae Alliance, Passifloraceae Alliance, Dilleniaceae, Huaceae, Picramniaceae, Sabiaceae” Springer Science & Business Media, 24 April 2007
4) Gren Lucas, Hugh Synge, International Union for Conservation of Nature and Natural Resources. Threatened Plants Committee “The IUCN Plant Red Data Book: Comprising Red Data Sheets on 250 Selected Plants Threatened on a World Scale” IUCN, 1978
5) Kerr, N. (1971). “Report on a Preliminary Nature Conservation Project, Island of St. Helena; July/August 1970.” IBP/4(71). Mimeo.
6) L'Héritier de Brutelle, C.L. (1787-8). “Geraniologia, seu Erodii, Pelargonii, Geranii, Monsoniae et Grieli historia iconibus illustrata.” Paris. t. 27.
7) Linnaeus, C. (1771). “Mantissa plantarum”. Stockholm. p. 569. (as Geranium cotyledonis).
8) Melliss, J.C. (1875). “St. Helena: a Physical, Historical and Topographical Description of the Island, including its Geology, Fauna, Flora and Meteorology”. London.
9) J. J. A. Van der Walt, P. J. Vorster “Pelargoniums of Southern Africa”, Volume 3 June, 1977
10)Geraniaceae Group “Superseded Genera of Pelargonium” Geraniaceae Group, 23 June 2004

Cultivation and Propagation: Easily growing in cultivation. Pelargonium cotyledonisSN|32394]]SN|32394]] is in cultivation in specialized collections and in botanic gardens. Seeds from ripe fruits germinate freely and new plants can be raised in greenhouses.
Soil: It does best with a mix that has almost no organic material at all. Perlite can be substituted for pumice, but it tends to rise to the surface of the mixture.
Water requirements. Water from early February to late April, then from early August to late November, at a minimum temperature of +14° C. Keep completely dry in summer and rather dry winter, at a minimum temperature of +8° C. Pelargonium cotyledonisSN|32394]]SN|32394]] in cultivation is usually so overwatered and overfertilized that it is hardly recognizable as the species that it is. Correctly grown, this is a beautiful, compact and dense plant.
Exposure: Light shade or morning sun in summer.
Frost Tolerance: Tender, it needs frost protection. Recommended minimum temperature is 8 °C or even above. Protect from frost.
Reproduction: There are two main ways to propagate members of the genus Pelargonium. Plant seeds any time of the year, but a spring or autumn sowing of seeds is usually most successful. Rooting cuttings of stems is another method.