Promiscuous Proteas

With its central pointed cone of dense black hair, Protea longifolia is one of the easier members of the genus Protea to recognise. The scientific name refers to the long narrow leaves, which are a better diagnostic character as there are other species with black hairy central cones. The leaves can be up to 20cm long but often only one centimetre across. This feature has carried across into one of its common names: Long-leaf Protea. The plants form bushes with a main trunk but rather weak branches. They therefore never reach the height of the taller proteas, rarely more than 1.5m high. The branches also tend to sprawl and bushes are often wider than high.

Protea longifolia (Proteaceae) flower

Distinctive black centres to Protea longifolia flowers

Protea longifolia (Proteaceae) flower

Weak branches of Protea longifolia form a rather untidy bush

Protea longifolia is a typical and common plant of Overberg fynbos. It occurs from the Kogelberg as far east as the Bredasdorp mountains. It is a reseeder and so at risk of local extinction if the fires are too frequent. Growing mostly in lowland areas below 150m, it has also lost habitat to commercial growing of proteas and is classified as Vulnerable. At Phillipskop it is common but sporadic around the lower slopes, often mixed in amongst stands of Protea repens. It starts to flower again about 4-5 years after a fire.

Although habitat destruction is the biggest risk to Protea longifolia, another more recent problem is appearing. Protea longifolia is not very choosy when it comes to accepting pollen and is one of the most promiscuous of all proteas. Natural hybrids of Protea longifolia have been recorded with Protea repens, Protea compacta and Protea lepidocarpodendron amongst several others. These all occur in the natural range of the species and are to be expected, though still rare, where the two parent species grow in close proximity. However, there is also the problem that where commercial proteas are grown, these cultivars or species from other parts of South Africa may interbreed with Protea longifolia. At Phillipskop, we have observed such a hybrid between Protea longifolia and commercial cultivars of Protea neriifolia.

Protea longifolia x neriifolia hybrid (Proteaceae) flower

Protea longifolia x neriifolia hybrid

Protea neriifolia (Proteaceae)

Cultivated Protea neriifolia

Protea longifolia x neriifolia hybrid (Proteaceae) leaves

Comparison of leaves of Protea longifolia (left), Protea neriifolia (right) and the hybrid (middle)

The hybrid of Protea longifolia and Protea neriifolia has the long leaves of Protea longifolia but they are slightly wider. The flowers also have the black central cone of Protea longifolia, but the black hairs on the reddish bracts and the shape of the flower are derived from Protea neriifolia. So far it is just a single plant but there is the risk of genes of Protea neriifolia introgressing into the natural population of Protea longifolia at Phillipskop. Is this a problem? More research is needed, but some of the concerns raised by conservationists have been expressed by Tony Rebelo of the Protea Atlast Project and can be read about here: http://www.proteaatlas.org.za/frankenflora.htm

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