Montag, 23. September 2013

Plant of the Day (23rd September, 2013) - Datura stramonium L.

The next “Plant of the Day” is Datura stramonium L.; a species from the Solanaceae family. The common German name of this plant is “Gemeiner Stechapfel”. In English, the plant is known as “Jimson weed” or simply “Datura”.

1) Description

D. stramonium - habitus

D. stramonium is an annual plant, which reaches heights between 30 and 120 centimeters. The bald, strong stalk is hollow and fork-like branched (two branches per node). The leaves are egg-shaped and have a long petiole. Their margin is irregular lobated and the ground of the leaf blade is a little bit wedge-shaped. There are no stipules. 

D. stramonium - leaf
 
The flowers are in the axils of the branches with one flower per axil. They are trumpet-like shaped and have five sepals and five petals. The bright-green sepals are fused and form a five angular tube. The petals are white and funnel shaped. An interesting feature is the flowering, because the flowers are closed at day and open at night. The reason for this is, that the primary pollinators of D. stramonium are moths, which are nocturnal. Flowering time is between June and October.

D. stramonium - flowers

However, the most distinctive feature of D. stramonium are the fruits. After successful pollination, the flower transforms into a large (between 4 and 6 centimeters), egg-shaped fruit with a spiky surface. This spiky fruit is also the reason for the German name “Stechapfel” (literally: “piercing apple”). Each fruit is a capsule with five flaps and contains over 400 black seeds.

D. stramonium - capsule, you can also see the seam
of the flaps

All parts of the plant, but especially seeds and roots, are very toxic due to the high content of Hyoscyamin and Scopolamin. Both belong to a a special group of Alkaloids: the Tropanes. The tropanes are typical for the nightshades and have a strong hallucinogenic effect. However, even small doses can cause respiratory paralysis and death.

the Tropanes of D. stramonium


Despite this, the seeds of D. stramonium are used as drug. This is however not recommend, because this is very dangerous due the high toxicity.

2) Distribution

Originally, D. stramonium was native to Mexico but today it can be found all other world as a neophyte. It was imported to Middle-Europe during the 16th century. The species grows on disturbed areas like ruderal wastelands, dumps but also in garvel pits and even roadsides. It prefers nutrient-rich places to grow and is also tolerant toward salt.

Freitag, 13. September 2013

Plant of the Day (September 13th, 2013) - Eryngium campestre L.

Today's “Plant of the Day” is Eryngium campestre L. from the Apiacae family. In German, the species has many different names like “Rolldistel”, “Radendistel” or “Krautdistel”. However, the most common name is “Feld-Mannstreu”. In English, the species is known as “Field Eryngo”.

1) Description
E. campestre - habitus

E. campestre is a perennial plant, which can reach heights between 20 and 100 centimeters ( to inches). The species can recognized easy on fields and meadows, because its ripped stalk and leaves have a greyish color. The whole plant is branched richly with sideways protruding branches.

E. campestre - umbel, bracts and leaves
 
The leaves are coarse with three leaves per node. They are irregular pinnate with a rough serrated margin and some spiky tips. All in all, the whole plant reminds to a thistle. However, thistles aren't a real genus or species of plant. It's more slang and describes many thorny and spiky plants on meadows or pastures. 

 E. campestre -umbels and bracts
 
As with all Apiaceae, the inflorescences of E. campestre are umbels. However, these umbels are more spherically than the umbels of other species from the Apiaceae family (like Heracleum sphodylium). The bracts of these umbels are very narrow and pointy. The actual flowers are inconspicuous with small, indistinguishable petals and sepals. Both have a green or white-green color. Flowering Time is between July and August.

E. campestre -umbel with flowers

The ripe fruits are spread by the wind, which brakes entire clusters out of the umbels. These clusters roll away and germinate miles away on suitable ground. In Botany, such a cluster like diaspore is a Tumbleweed, while this special kind of spreading is called Chamaechorie. You may know it from old western movies.

2) Distribution

E. campestre is native to Western-Europe and Eurasia. In middle-Europe, especially Germany, it is a not so common plant, which grows mostly in the valleys of the great rivers like the Rhine. In higher regions, the species is mostly missing. As a result, E. campestre is protected by law in Germany as a “threaten species”.

 such a meadow at the Rhine is a habitat for
E. campestre

The species prefers warm and sunny places and dry soil with a low contain of nutrient. Its natural habitat are dry meadows (on lime) but it can also found on ruderal wastelands and pastures.


Freitag, 6. September 2013

Plant of the Day (September 7th, 2013) - Butomus umbellatus L.

Our actual “Plant of the Day” is Butomus umbellatus L. from the Genus Butomus, which is the only genus of the Butomaceae family (mono-generic. In German, common names are “Schwanenblume” or “Blumenliesch”. In English, B. umbellatus is known as “flowering rush” or simply “grass rush”.

1) Description

B. umbellatus is a larger, perennial plant, which reaches average heights between 50 and 150 centimeters. The stalk is round and completely leafless. All of the leaves are located at the base of the stalk. It's very bendable, what is also the reason for the German name “Schwanenblume” (literally translation: “cygne's flower”). The stalk also contains some clear, natural latex.

B. umbellatus - inflorescence

There is also a creeping rhizome, which is about 1 centimeter thick. Normally, offshoots are missing but sometimes, there are some buds along the whole rhizome.

 B. umbellatus - stalk & leaves

As a water plant, there are two kind of leaves: underwater and normal leaves. Normal leaves are very long and about 1 centimeters broad. With their slightly keeled habitus, they look a little bit like a grass leaf. As with all monocotyledons, the leaf-veins are parallel to each other. When growing in deeper water, the underwater leaves become much longer and ligament-like. 

B. umbellatus - water leaves
 
All in all, the species has a reed or rush like habitus. This is also the reason for its common names (“flowering rush” in English/ “Blumenliesch” in German), because the whole plant simply looks like a flowering rush or a flowering grass.

 B. umbellatus  - normal leaf en detail (with water leaves
in the background)

The inflorescence of B. umbellatus is (as the name suggests) a single, terminal umbel with an average of 30 flowers. As a monocotyledon, these flowers are ternate and have two circles of flowers: an inner circle and an outer circle. Each circle consists of three, egg-shaped petals, which have a light pink (or white) color and a deep-purple band of leaf-veins in the center. There are nine stamens in the center. Each has red filaments. Flowering time is between June and August. *)

B. umbellatus - flower (with pollinator)

The ripe fruits are follicles (“Balgfrüchte” in German) which opens in order to release the seed, which is widespread by the wind. Because the plant grows in the reed beds, the pedicel extended itself after pollination. So, the ripe fruit is lifted over the grasses and exposed to the wind.

B. umbellatus - inflorescence with some ripe fruits

*) This may vary within the flower. Sometimes, the petals of the outer circle are whiter than the flowers of the inner circle or the band isn't so distinctive.

2) Distribution & Habitat

B. umbellatus is native to Middle-Europe, Asia and North Africa. However, it was also introduced to North America as ornamental plant and is now a neophyte. The species is a typical plant of wetlands and grows in bogs, marshes, reed beds and floodplains. It prefers wet, muddy soils and has no problem with periodical floods. It's not protected but rare in Middle-Europe.

B. umbellatus - in its typical habitat

Some parts of the plants were used in past. For example, the highly bendable stalk was used to weave baskets. The rhizome contains a lot of starch. Therefore, it was baked and eaten like bread. In Asia, it's eaten today but more for medicinal reasons.