Dienstag, 24. April 2012

Plants of the Day (April 24th, 2012) - Elegia carpensis (Burm. f.) Schelpe & Restio tetraphyllus Labill.

Today, my blog becomes very exotic, because this time, I want to show you two plants from a family, which can only be found at the coastal regions of the Southern hemisphere. I mean the Restionaceae, while the two species are Resito tetraphyllus Labill. and Elegia capensis. (Burm. f.) Schelpe
Common English names for the first one are “Tassel cord rush” or “Plume rush”, while the second one is called “horsetail restio”. In German, R. tetraphyllus is known as “Strickbinse” while E. carpensis is known as “Elege”.

The Restionaceae are grass-like herbs. In fact, they fill in the role of the Poaceae in the Southern Hemisphere.

a) Elegia carpensis (Burm f.) Schelpe

E. carpensis is a large (maximum height: 3 metres or 9.84 feet), upright growing plant with thick, bamboo-like stalks, which are divided in nodes and internodes (like the Poaceae). Each node has a dense whorl of narrow, needle-like branches. Because of this, the plant looks a little bit like a horsetail, which is also the reason for its English name. The actual leaves are very small and inconspicuous. In fact, the whole photosynthesis is made by the green stalk.

E. carpensis - habitus (here you can see the similarity
to a horsetail)

Another distinctive feature of E. carpensis is the large, leaf-like structure at every node (similar to the Ligula of the Poaceae), which protects the growing point of the stalk. When they gets older, this structure becomes brown and leathery and fells finally off, if flowering time is reached.

The plant also have perennial, underground rhizomes.

E. carpensis - foliage; the brow spot on the
right side is the leaf-like structure)

E. carpensis is dioecious (pure male or female plants). The inflorescences of both genders are panicles with small, radial to star-shaped flowers. The six tepals are arranged in two circles with three tepals per circle. They have a brown (young) to dark-brown (old) colour. The ripe fruit is a one-seeded nut. Flowering time is from October to November and ripening in March.

As the name suggest. E. carpensis is native to South Africa (the regions arround the Cape), where it forms dense stocks. It grows in an altitude between sea-level and one mile (1.600 kilometres) on sandy, nutrient-poor soils. It prefers wet places, but can also grow on dry soils, but here, it is smaller and has a brighter colou

b) Restio tetraphyllum Labill.

R. tetraphyllum (in some literature also Baloskion tetraphyllum (Labill.) L.A.S.Johnson & B.G.Briggs) is an evergreen, grass-like herb, which grows in dense tufts. The slender, upright stalks have a blue-green colour. The leaves are very small and lie flat on the stalk. The plant reaches heights between 50 and 160 centimetres (19.7 to 63.0 inches).

R. tetraphyllum - habitus with inflorescences

Like E. carpensis this species have underground rhizomes, which are used for vegetative propagation.

The inflorescence is one terminal panicle. R. tetraphyllum is also dioecious with male and female plants. In both cases, the flowers are small spikelets (“Ährchen” for my German readers). The number of this spikelets is varying. Some flowers have only a few ones, while other individuals can have up to 400 spikelets per panicle.

R. tetraphyllum - inflorescences (possibly female spikelets)

Male spikelets are globule and have one circle with six, reddish-brown tepals. The glumes (“Hüllspelzen”) are oval and pointed. Female flowers are also reddish-brown, but more oval or elliptical. Their glumes are broader and have an awn. They've also only 4 tepals. The ripe fruit is a grey-brown nut. Flowering time is in the southern spring and summer, while ripening time is in the southern autumn.

R. tetraphyllum is native to Australia. The main distribution area are the Eastern regions of New South Wales, but the species can also be found in Queensland, Victoria, South Australia and Tasmania. It grows on river banks on swampy and sandy soils

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