Dienstag, 4. Dezember 2012

Plant of Day (Dezember 4th, 2012) - Hypericum canariense L.

Today's “Plant of the Day” is Hypericum canariense L. from the Hypericaceae family (St. John's Worth). In English, the species is known as “Canary St. John's Worth” and in German as “Kanarisches Johanniskraut”. In Spanish, the species is called “Grenadillo”.



H. canariense - inflorescence & leaves


Unlike the more common Hpericum perforatum L. (St. John's Worth), this species is a medium high shrub, which can reach a maximum height of nearly 3 meters (9.8 feet). A total height of 7 meters (22.9 feet) is also possible. It grows multi-stemmed and the smooth bark has a medium brown color. There is also a richly branched rhizome, which is used to anchor the plant in the soil.

H. canariense - stems

The narrow leaves are lanceolate and between 2 and 7 centimeters long. They have a prominent, white leaf-vein on their dorsal site and are arranged in an opposite leaf-pattern. Another prominent feature is the thick, waxy cuticula. However, H. canariense isn't evergreen. The foliage is green during winter but change its color later to an orange during summer. At the end of the summer, the leaves are dropped.

H. canariense - leaves; on this picture, you can see
the white leaf-vein and the opposie leaf-pattern

The inflorescence are cymes, while the flowers are similar to the flowers of H. perforatum. There are five sepals and five petals. The small sepals are ovate and have a cilliated margin. The petals have a orange to yellow color. Like the most species from the Genus Hypericum species has numerous of anthers. There are also three stigmas. The ripe fruits are black, leathery capsules, which open in late summer (between June and August) after ripening.

H. canariense - inflorescence; the three styli per are encircled 
also on this picture, you can see the anthers (a), petals (p) and sepals (s)

As the name suggest, H. canariense is native to the Canary Island, which are located before the shores of West Africa. More precisely, the species grows only on the five western islands (El Hierro, La Palma, La Gomera, Tenerife and Gran Canaria) of this group of islands. It grows on the slopes of former volcanoes between 150 and 2000 metres and is part of the laurel forests. These are forests of xeromorphical shrubs and small trees, which have adapted to the high temperatures during spring and summer (the waxy leaves are an example for such an adaption).

However, H. canariense can also be found in North America and Western Australia as Neophyte. For example, the species is very common in the counties of Los Angeles in California (USA) and Victoria (Australia). Probably, this individuals are former ornamental plants, which started to grow wilde, because the environmental conditions are the same like on the Canary Islands (hot summers, laurel forests and rocky slopes)

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