Dienstag, 17. Mai 2011

Plant of the Day (May 17th, 2011) - Carex nigra (L.) Reichard

In the Article about my small field trip to Lake Unterbach, I shown you a picture of Carex nigra (L.) Reichard. Now it's time, to get closer look on this species.

 C. nigra (L.) Reichard - ears
(male: brown; femal: blackgreen)

Carex nigra (L.) Reichenbach belongs to the Cyperaceaeae family. It's a grass-like herb and between 10 and 40 centimetres high with long, narrow leaves, which has a grey-green top and a dark-green underside. They are sitting in dense clumps.

The leaves are also epistomatic, that means, that the stomata are located at the top of the leaves. This also the reason, why the leaf-top is grey-green.

C. nigra (L). Reinhard - leaves
(look a the white lines of stomatas)

The flowers are sitting in ear-like inflorescences.

C. nigra (L.) Reinhard - flowers

The Genus of Carex is divided into three sub-genera: the Heterostachyae, the Homostachyae and the Monostachyae, what depends on the shape of the ears. C. nigra belongs to the Heterostachyae sub-genus, because the ears with the male flowers differs from the ears with female flowers.

The most two male ears are located at the top of the floral axis. They are brown, black or dark-purple. The 2 - 4 female-ears sitting at the middle of the axis. They are dark-green and have black chaffs.

C. nigra (L.) Reinhard - male ears (brown)
at the top and female ears (dark green) in the middle

C. nigra is widespread in almost the entire, northern hemisphere (Europe, Asia, North Africa and North America). It grows at acid, wet places like swamps, wetlands or floodplains. The species prefer nutrient-poor soils.

The Cyperaceae look similar to the common grasses (Poaceae), but there are some differences between Cyperaceae an Poaceae.

1) Shape of the Shoot axis: First, the Cyperaceae have a triangular shoot-axis without any nodes; the Poaceae on the other side have a round shoot-axis with nodes.

2) Interior of the shoot-axis: The shoot-axis of the Cyperaceae is filled out by marrow; the shoot-axis of the Poaceae is hollow.+

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