Montag, 28. Mai 2012

Plant of the Day (May 28th, 2012)- Viburnum rhytidophyllum Hemsl.


This time, I've a species from the Adoxaceae family for you. This species is Viburnum rhytidophyllum Hemsl.; known as “Runzelblättriger Schneeball” or “Immergrüner Schneball” in German and as “Leatherleaf Viburnum” in English. The Chinese name is 皱叶荚蒾, which means “wrinkled leafed Viburnum”.

V. rhytidophyllum - habitus

It's an evergreen shrub or tree, which can reach a height of 4 metres (13.1 feet). The bark has a greyish colour and young branches are covered with hairs. Because of these hairs, the branches have a yellowish or reddish colour. Later, these hairs fall off and the branches are getting bald.

V. rhytidophyllum - leaf (dorsal site)

The lanceolate leaves are arranged in a decussate leaf-pattern. They have no stipules but a long petiole, which is also very hairy. The leaf-blade of young leaves is reddish to brownish but gets a deep green colour on the shiny dorsal site, when the leaves become older. The ventral site is always brighter. Both sides of the leaf-blade are very leathery and deeply furrowed by the leaf-veins. This leathery leaves are also the reason for the scientific name (“rhytidophyllum” means something like “leathery leafed”).

V. rhytidophyllum - inflorescnece

The inflorescence is a umbel-like cyme with many small, radial flowers. V. rhytidophyllum is dioecious, but in the most case, only the flowers in the centre of the inflorescence are fertile while the peripheral flowers are sterile. In both cases, each flower consists of five green sepals and five white petals. The sepals are fused to a tubular structure and also covered with (star-shaped) hairs. The petals are also fused but nearly bald. Flowering time is from April to May.

The fruits are red drupes, but they change the colour to black with the time.

V. rhytidophyllum - leaves (different ages)

V. rhytidophyllum is native to central and Southern China and can be found in the undergrowth of forests. The species is very undemanding towards the growing conditions and grows in heights between 700 and 2400 metres. As evergreen shrub with large inflorescences and distinctive leaves, it's also a very popular ornamental plant for gardens and parks; especially for hedges in order to block the line of sight.

Freitag, 25. Mai 2012

Plant of the Day (May 25th, 2012) -Rhododendron forrestii var. repens (I. B. Balfour & Forrest) Cowan & Davidian


Today's “Plant of the Day” is another Rhododendron from the Ericaceae family. This time, I want to show you Rhododendron forrestii var. repens (I. B. Balfour & Forrest) Cowan & Davidian In Germany, the plant is known as “Zwerg-Rhododendron” (Dwarf-Rhododendron). Unfortunately, I didn't found an English name for the wild form (the literally translation of the scientific name would be “Forrester Rhododendron”) but in Chinese, this plant is called 紫背杜鹃.

R. forrestii var. repens - habitus

It's a small, evergreen shrub, which can reach a maximum height between 20 and 90 centimetres (7.9 to 30.4 inches). The small leaves are dark-green and have a leathery, textured surface. Their petiole is nearly 10 millimetres long and the leaf-blade has an elliptical shape. There are also some leaf-glands.

R. forrestii var. repens - habitus

The inflorescences are umbel-shaped racemes with a glandular petiole. The flowers have a tubular form with conspicuous, crimson-red petals. The sepals are green and form a fleshy, saucer-like structure. Flowering time is in May. The ripe fruits are inconspicuous, cylindrical capsules.

R. forrestii var. repens - habitus

R. forrestii is native to China and Tibet. The plant is very undemanding towards the growing conditions and grows on rocky slopes and pastures. However, because of the very beautiful, red flowers, the species has become a very popular ornamental plant for gardens and parks (as with the most Rhododendrons). In the Twenties of the 20th century, the German Botanist Dietrich Hobbie began with the breeding of new sorts from the wild forms of the Genus Rhododendron. He created also new sorts of R. forrestii var. repens., which were exported all over the world. The most popular sorts today are “Baden-Baden” (named after a German town), “Scarlett Wonder”, “Frühlingszauber” (German for “Magic of Spring”) and “Bengal”.

Please note: All pictures were taken by Christopher Schwerdt. I have his permission to use these pictures in my blog.

Montag, 21. Mai 2012

Plant of the Day (May 21st, 2012) - Rhododendron catawbiense Michx.


Today's “Plant of the Day” is Rhododendron catawbiense Michx.; a Rhododendron from the Eriaceae family. With over 1.000 known species, the Genus Rhododendron is very, very species rich. In German and English, this plant is known as “Catawba-Rhododendron”, what is the literally translation of the scientific name (the Catwaba are a tribe of native Americans). However, in English, the plant is also known as “Purple-Laurel” and “mountain rose bay”. 

 R. catawbiense - habitus

It's a medium high, evergreen shrub, which can reach a maximum height of 7 metres (20 feet) but the average height is normally between 2 and 3 metres (6 to 10 feet).
The dark-green leaves are elliptical shaped with a simple margin. They have a long petiole and follow the alternative leaf-pattern. Their surface is leathery.
The bark is grey.

R. catawbiense - flowers

The inflorescences are umbel-shaped racemes with five to ten large, radial flowers. Each flower has five, green and narrow sepals and five petals. These petals are purple to magenta and have some speckles on the inside. The stamens (two circles with five stamens per circle) are also magenta, while the stylus has a dark-purple colour. Flowering time is normally in May and the ripe fruit is a capsule.

R. catawbiense - leaf

R. catawbiense is native to North America; more specifically in the southern regions of the Appalachian mountains (e. g. the states of Virginia and Georgia). It prefers, sunny to shady places and fresh to moist soils. But it hates dryness and heat.

R. catawbiense -an inflorescence right before flowering

As evergreen shrub with large, beautiful flowers, R. catawbiense is also a very popular ornamental plant for parks and gardens. In fact, this applies to many species from the Genus Rhododendron. So, there are many sorts and hybrids of Rhododendrons, what makes an exact determination very difficult because these sorts differ in many characters from the wild forms (e. g. the colour of the flowers, the shape of the leaves and so on).

 R. catawbiense -a sort with rose flowers

Montag, 14. Mai 2012

Plant of the Day (May 14th, 2012) - Myosostis sylvatica agg.


Today's “Plant of the Day” is Myosostis sylvativa (L.) Hill. from the Boraginaceae family. In English, this plant is commonly known as “wood forget-me-not” while in German, it's called “Wald-Vergissmeinnicht”.

M. sylvatica - habitus

It's a herb, which can reach heights between 15 and 45 centimetres (5.9 to 17.7 inches).
The plant grows upright and in dense stocks. Each plant has a leaf rosette at its base, which are going over into the bracts gently. The bracts are broad and have a lanceolate shape. It's also important, that the rosette leaves are stalked and the bracts are sitting.

M. sylvatica - leaf

The entire plant is covered with protruding bristles, which is a distinctive feature of all Boraginaceae.

 M. sylvatica - stem, bracts & bristles

Flowering time is between April and June. The inflorescences are umbel-shaped racemes with radial flowers. The green sepals are narrow to lineal and also covered with bristles. The petals are reddish at first, but become sky-blue later. There are also yellow scales, which narrow the corolla tube.

M. sylvatica - inflorescence

The pollen is very small with only 4 X 6 micrometres; making the pollen of M. sylvatica to the smallest pollen of the German flora. This is unusual, because small pollen are often distributed by the wind, but at M. sylvatica, the pollinators are still insects.

The ripe fruit is a shizocarp “Klausenfrucht”. This is a fruit, which consists of two carpels but divides itself into four smaller fruits after ripening. The Klausenfrucht is typical for the Boraginaceae and the Lamiacae.

M. sylvatica - flowers

M. sylvatica is native to Middle Europe, where it grows on fresh, nutrient-rich soils. So you can find it e. g. on meadows, pastures or at the edges of woods. Some sorts are also very popular garden plants, which can also start to grow wild. So, it's likely, that my photos show some of these sorts, but I cannot say what.

Freitag, 11. Mai 2012

Plant of the Day (May 12th. 2012) - Prunus laurocerasus L.


Sorry for the long break, but I was sick this week and couldn't write an article.

So, today's “Plant of the Day” is one of the most common evergreen plants in gardens and parks. It's Prunus laurocerasus L. from the Rosaceae family. In Germany, we call this species “Lorbeerkirsche” while in English it's known as “cherry laurel”. In some literature, this species is still known as Laurocerasus officinalis L.

P. laurocerasus - habitus

It's a big shrub, which can reach an average height of 6 metres (but can also reach heights over 10 metres).
The leathery leaves are elipitcal and very simple with an entire margine, which can be a little bit bent. The dorsal site is dark green and shiny, while the ventral site is bright green and with a couple of nectaries at the base of the leaf-blade.

P. laurocerasus - leaves

The function of the leaf-nectaries is the attraction of ants, which eats vermin like caterpillars or aphids, which can injure the leaves.

P. laurocerasus - single leaf (dorsal site)

P. laurocerasus - single leaf (ventral site)

As member of the Spiraeoideae, a sub-family of the Rosaceae, this species has no stipula.

The inflorescences are upright racemes with many small, radial flowers.
Each flower consists of five, bright-green sepals, five white petals and a lot of stamens and carpels. The stamens are very long and much longer than the stylus. There are also nectaries at the ground of the flowers, giving them a orange colour in the centre.
Flowering time is between April and June. The ripe fruit is are black drupes, which are eaten by birds.

P. laurocerasus - inflorescence

All in all, P. laurocerasus looks similar to the real laurel (Laurus nobilis L.).; especially the leaves. This is also the reason for the name “cherry laurel”, but there is no relationship between this two species, because Laurel belongs to the Lauraceae family.

P. laurocerasus - single flower: s = sepals; p = petals;
styl = Stylus; sta = Stamen; n = nectaries

P. laurocerasus is native to Asia minor and grows wild in Anatolia, the Caucasus and North-Iran. It prefers fresh and shady places and grows in the undergrowth of forests in altitudes from sea-level to 2.000 metres. However, P. laurocerasus is also a very popular shrub for gardens and hedges and planted all other the world today as evergreen ornamental plant (however, this plant isn't so robust towards very hard and long periods of frost as some people maybe think).

P. laurocerasus - dryed fruit from the last year

The species can be toxic. Leaves and seeds contain a chemical compound called “Prunasin”. If this Prunasin comes in contact with gastric acid, it can transform into dangerous cyanide. However, Prunasin is in the seed of every cherry (Genus: Prunus); making P. laurcerasus not more toxic as other cherries like Prunus cerasus L. or Prunus avium L.

In Turkey, the pulp of the ripe fruits is even used to make bitter tasting jam. The fruits are also eaten as dried fruits.

Samstag, 5. Mai 2012

Plant of the Day (May 5th, 2012) - Lolium perenne L.


As announced, today's “Plant of the Day” is Lolium perenne L; another, very common grass of turfes. It's a member of the Poaceae family and known in Germany as “Ausdauernder Lolch”or “Deutsches Weidelgras”´, while in the English language, it's known as “English Ryegrass” or “Perennial Ryegrass”.

L. perenne - habitus

It's a grass, which can reach heights between 20 and 60 centimetres.
The upright growing, smooth stalk has a dark-green colour and they typical nodes of the Poaceae. The narrow leaves are until 20 centimetres long and only 4 to 6 millimetres wide. They are also a little bit serrated.
L. perenne has the ability to spread out per underground offshoots, so it quickly forms a dense turf.

L. perenne - shoot and leaf

The species is an ear-grass, so the inflorescences are sessile spikes with 6 to 10 spikes per plant and one terminal spike at the end of the shoot.
These spikes are arranged in to alternating rows, what is also a characteristic feature of the Genus Lolium (and a good difference to the similar looking Genus Elymus). They are up to 10 millimetres long and have only one one glume (which is another distinctive feature of this Genus) and no awn. The reason for the single glume is the arrangement of the spikes in alternating rows. Flowering time is between May and October.

L. perenne - infolrescence

L. perenne is native to the Europe but is a cosmopolitan today and can be found all other the World as Neophyte. It is a very popular grass for gardens and turfs (also playgrounds) because it grows fast and is very insensitive to mechanical stress. It prefers nutrient-rich, fresh soils and a temperate climate, but is a little bit sensitive to heath and frost.

Please note: It's not unusual for this species to interbreed with other species. A very common hybrid is x Festulolium ascendens A. & Graeb.; the result of an interbreeding between Lolium perenne L and F. pratensis, which I've shown you in my previous post.
In some cases the hybrid looks more like L. perenne and in other cases more like F. pratensis. Therefore, it's possible, that my pictures show this hybrid, but I cannot say surely.

Dienstag, 1. Mai 2012

Plant of the Day (May 1st, 2012) - Festuca pratensis Hung.


Spring is not only the time of beautiful flowers but also the reawakening of the grasses. After their “hibernation”, the different grasses starts to grow and the time of mowing comes near. One of this typical garden-grasses is today's “Plant of the Day”: Festuca pratensis Huds. from the Poaceae family. In German, this species is known as “Wiesen-Schwingel” while English speaking people maybe know it as “Meadow fescue”.

F. pratensis - habitus

F. pratensis is a perennial grass, which can reach heights between 30 and 120 centimetres (11.8 to 51.8).
The stalk grows upright and is a little bit bent. It has also the typical nodes of the Poaceae. 
The dark-green leaves are until 10 centimetres long and 5 mm wide. They are completely bald and hang down limply. The leaf-blades are very smooth and have small auricles at their base. The ligula is very small (under 1 millimetre).
There are also basal-leaves, which have a different morphology. They are small, brown and fibrous.
The plant grows in loose eyries

F. pratensis- roots & basal leaves

The inflorescence is the typical double-racemes of the Poaceae with the strongly reduced internodes. F. pratensis belongs to the panicle-grasses, so the ears have long stalks and form a slightly overhanging panicle.
The actual ears are a little bit cylindrical. Each ear consists of 5 to 8 small flowers with lanceolate lemmas and very short glumes. In the most cases, the ears are green, but sometimes, they also have a reddish colour.
Flowering time is between June and July (I made these pictures last summer); the fruit is a one-seeded nut (“Karyopse” in Botany).

F. pratensis - pannicle from above

F. pratensis is native to Europe and the temperate regions of Asia, but can also be found today in America, Australia, New Zealand and South Asia as neophyte. It prefers fresh places and nutrient-rich soils (especially on lime). It grows from sea-level to an average height of 1500 metres (0 to 4921.3 feet).

F. pratensis - habitus

Because it's very insensitive to mechanical stress, F. pratensis is a popular grass for turfs and planted in many gardens all over the world. In fact, it's a characteristic species for nutrient-rich pastures. Another reason for popularity of F. pratensis is also its high value as forage grass.

Please note: It's not unusual for this species to interbreed with other species. A very common hybrid is x Festulolium ascendens A. & Graeb.; the result of an interbreeding between F. pratensis and Lolium perenne L., which I will show you in my next post.
In some cases the hybrid looks more like F. pratensis and in other cases more like L. perenne. Therefore, it's possible, that my pictures show this hybrid, but I cannot say surely.