Freitag, 31. August 2012

Plant of the Day (August 31st, 2012) - Helianthus annuus L.

After I've presented Chicory; today's Asteraceae is from the Sub-family of the Asteroideae. This “Plant of the Day” is also one of the most popular Asteraceae in the World. I'm speaking of Helianthus annuus L.: the sunflower (“Sonnenblume” in German).

H. annuus - habitus

The sunflower is a large, annual plant, which can reach heights between 1 and 2,5 metres (3.3 to 8.2 feet). The stalk grows upright and is covered with many bristles; giving the stalk a rough surface. The leaves are arranged in an alternate pattern. They are heart-shaped and have a long petiole.

The name “sunflower” comes from the ability of the species to move its leaves and young buds after the sun from east to west. This ability is called Heliotropism and is made possible by special cells: the so called motor cells.

H. annuus - inflorescence

The inflorescence is a large, terminal heads. Unlike C. intybus, this inflorescence consists of two different types of flowers: tubular disc flowers in the centre and ray flowers in the periphery. Only the disc flowers are fertile. But they are very small and inconspicuous with brown, scale-like petals. The ray flowers can have many colours but the most common is the typical golden yellow of the sunflowers.

H. annuus - leaves & stalk

The ripe fruits are small, pyramidal nuts; the so called Archenes. They are used to make sunflower oil or as grain. They contain unsaturated fatty acids and many vitamins like Vitamin E, Vitamin B or Vitamin A.

The wild sunflower is native to North and Middle America and was domesticated over 2500 years by the Incas and the indigenous people of America. In the 16th century, the sunflower was brought to Europe by the Spanish Conquistador Pizarro as ornamental plant. The species was also very popular in Old Russia. The domesticated sunflower needs fresh, nutrient-rich soils. Sometimes, some individuals starts to grow wild.

Montag, 27. August 2012

Plant of the Day (August 27th, 2012) . Cichorium intybus L.

As I promised, my Blog is back with a new “Plant of the Day”. This plant is Cichorium intybus L. from the Asteraceae family (sub-family: Cichorioideae). In German, this species is known as “Gemeine Wegwarte” or “Zichorie” and in English as “Chicory”.

C. intybus - habitus

It's a herbaceous plant, which can reach heights between 30 to 200 centimetres (0.98 to 6.6 feet). The stem is branched richly. The leaves are not uniform. Lower leaves are lobated, serrated or even pinnate. Their leaf-veins are also often covered with small bristles. The upper leaves are long and lanceolate with a very broad leaf-base, which can embrace the whole stalk. The leaf-veins of the upper leaves aren't hairy.

C. intybus - inflorescence & bracts (here you can
see how the bracts embracing the stalk)

The inflorescences are the typical heads of the Asteraceae. An inflorescence consists of many small flowers, which form a fake, large “flower”. As member of the Cichorioideae, the inflorescences of C. intybus are all cygomorphic ray flowers. Each flowers has five azure (in some rare cases white) petals, which are fused to form one large, fake “petal”.

This seems to be a little bit complicated, but I will explain the difference between the flowers of the two large sub-families of the Asteraceae (Cichorioideae and Asteroideae) in a future article.

C. intybus - basal leaf

C. intybus is native to Europe, Asia Minor and Northern Africa but can also be found as neophyte in other regions of the world like North America or South Africa. It grows on roadsides, ruderal wastelands and pastures, what is also the reason for the German name “Wegwarte” (way keeper). This plant is typical for trodden trails.

C. intybus - inflorescence

In past, this plant was used to cure diseases of spleen, liver and bile (C. intybus is one of only a few medicinal plant for the spleen). It was also used as laxative and as appetizer. Even today, chicory is used as a spice and vegetable.

Chicory is also part of many medieval legends. For example, the people believed, that this plant had the power of love and sensuality.

Dienstag, 21. August 2012

Update

Hi everybody,

in my last Post, I told you, that my Blog has a little break because of personal circumstances. This break will be over soon and a new Posting will be published at Monday

Freitag, 10. August 2012

Important message

Dear Readers and Visitors,

because of personal circumstances, I may not be able to post new postings in a regular turnus during August. I'll try to write some posts but don't wonder, if it will not be two posts per week. Don't worry, this blog is still allive and I'll write two entries per week again from September.

Samstag, 4. August 2012

Plant of the Day (August 4th, 2012) - Verbascum speciosum Schrad.


Today's “Plant of the Day” is Verbascum speciosum Schrad. from the Scrophulariaceae family. In German, this species is known as “Pracht-Königskerze” (magnificent mullein) and the common English name is “showy mullein”. As relatively young part of the German Flora, there are not so many informations in German literature but more on that later.

V. speciosum - habitus

As the name suggest, V. speciosum is a handsome and showy plant, which can reach heights between 60 and 230 metres (1.9 to 7.6 feet). The strong stalk grows upright and is only branched in the upper regions. Thereby, the plant looks a little bit like a candlestick. The whole stalk is covered with smooth, star-shaped hairs.

V. speciosum - stalk & leaves

The leaves are also hairy, what gives them a grey-green colour. They have a simple margin, which is not serrated or indented in any manner. However, the leaves in the upper region of the plant embrace the stalk nearly, forming some small “auricles”. All leaves have small humps at their nodes.

V. speciosum - a single leaf

All in all, the leaves were arranged in such a way, that they form a kind of funnel. In this way, the plant is able to guide rainwater to the roots.

V. nigrum - inflorescence

The inflorescences are terminal racemes with many flowers. These flowers are wheel-shaped and between 10 and 26 millimetres in diameter. The petals are yellow and all five stamens are fleecy haired. Flowering time is between June and July. The ripe fruit is a capsule with many seeds inside.

V. speciosum - flower with the woolly stamens

V. speciosum is native to South-East Europe but loose stocks can be found also in Germany and other Parts of Europe as neophyte today. It prefers warm, sunny to semi-shady places. So it can be found on clearings, dry meadows or the edges of forests. In its new areas, V. speciosum grows on ruderal wastelands and at roadsides or railway tracks.

The spread of V. nigrum is a relatively recent phenomenon and was often the subject of researches during the last years. Thereby, there are only a few informations about its growing conditions, area of distribution and so on.