For the identification of insects and other fauna and flora of South Africa.

Tuesday, October 7, 2014

Pelargonium tetragonum

Family Geraniaceae
Distribution and habitatThis pelargonium species has a rather limited distribution in the Langeberg range in the southern Western Cape. It is only known over a range of not more than 50 km, from the vicinity of Montagu in the west to near Riversdale in the east. It occurs mostly at altitudes of 300 to 600 m. Near the coast it forms a component of the vegetation type Coastal Renosterbos veld, dominated by Elytropappus rhinocerotis. In the mountains it occurs in False Macchia, which is considered to be an in-between vegetation type between Dohne Sourveld and true Fynbos. These vegetation types consist of dry, low, shrubby, sclerophyllous (hard-leaved) vegetation. P. ternatum grows in rocky terrain often in well drained sandy soil. The distribution area receives an annual rainfall of about 200 to 400 mm near the coast and as high as 600 mm in the mountains. The rainfall pattern is evenly distributed throughout the year. The summer months become quite hot, winters are mild, and light frost is experienced at elevated localities. According to Van der Walt & Vorster (1981) “After a veld fire in Garcia's Pass in the 1976 an extensive population of P. ternatum appeared on the burnt section, suggesting that the species acts as a pioneer in an early stage of plant succession.”
Derivation of name and historical aspects|Pelargonium ternatum belongs in the Geraniaceae family, a large cosmopolitan family of approximately 11 genera and 800 species in subtropical and temperate regions of the world. There are approximately 270 species of Pelargonium which occur in S, E and NE Africa, Asia, St Helena, Tristan da Cunha, Madagascar, Australia and New Zealand, most of which (219 species) occur in southern Africa. The genus Pelargonium gets its name from the resemblance of the shape of the fruit to the beak of a stork, pelargos in Greek, while the specific name ternatum, in Latin, means 'in threes', and refers to the three leaflets or lobes of the leaves.
EcologyThe seed is adapted to wind dispersal; it is light in weight and has a feathered, spiral, tail-like attachment. When the seed lands and there is sufficient water in the soil, the tail acts like a drill, twisting the seed into the soil so that the seed can anchor itself in the ground and is thus prevented from being blown away, or carried away on moving animals.

Info: http://www.plantzafrica.com