Freitag, 2. August 2013

Plant of the Day (August 1st, 2013) - Heracleum sphondylium L.

Today's „Plant of the Day“ is Heracleum sphondylium L. from the Apiacae (aka Umbeliferacae) family. In German, the species is known as “Wiesenbärenklau” and in English as “Common Hogweed”. The plant is the “smaller brother” of Heracleum mantegazzianum Sommier & Levier; the notorious “Giant Hogweed” (Riesenbärenklau).

 H. sphondylium - habitus

1) Description

H. sphondylium is a larger, perennial plant, which can reach heights between 50 and 150 centimeters (19.5 to 59 inches). The stalk is furrowed and covered with bristles. Its also hollow. The leaves are arranged in a semi-rosette. In contrast to a real rosette, leaves are also along the stalk but concentrated in the lower regions.

H. sphondylium - leaf-sheath and stalk

The leaves are irregularly pinnate to lobed. Their margin is roughly serrated. Another distinctive feature of this plant is the puffed-up leaf-sheath at the base of each leaf. The bracts of the umbels, the invulucrum, are very narrow and nearly filamentous. 

H. sphondylium - pinnate leaf of a young plant

As with all Apiaceae, the inflorescences of H. sphondylium are umbels. Specifically, these umbels are double umbels, which consist of two smaller umbels. Each umbel consists again of many small flowers with five, white petals per flower. The flowers are radial, but flowers in the periphery of the umbel are a little bit larger than the flowers in the center.

H. sphondylium - inflorescence

All in all, the flowers create a larger, fake flower, which attracts pollinators like bees and beetles. Since the nectar isn't very deep, H. sphondylium is visited by many different pollinators, because they doesn't need a long proboscis.

H. sphondylium - flowers; the flowers in the periphery
are larger than the flowers in the center

Flowering time is between June and September and the ripe fruit is a Achene. This is a special form of the nut with double wings. So, the ripe fruit is able to fly with the wind for spreading.

H. sphondylium - double achenes wth wings

Unlike H. mantegazzianum, H. sphondylium isn't so dangerous and its liquid doesn't caused serious burns and injuries. However, the liquid of H. sphondylium can caused itchy skin irritations.

H. sphondylium - leaf

2) Habitat

Unlike H. manzegazzium, H. shpondylium is native to Middle-Europe and not a Neophyte. It can be found e. g. on pastures, meadows and along creeks but also on ruderal wastelands, if the soil is deep enough for the roots. Other common habitats are riparian forests or ditches. H. sphondylium prefers fresh and nutrient-rich places and a loose soil. It's typical for oceanic regions with wet winters and summers, which are mild in the average.

H. sphondylium - pastures and floodplains are typical

The plant is a little bit toxic, but young plants aren't. So, young individuals of H. sphondylium can be used as vegetable or fodder.

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