The World´s Tree Species: 2011.04

Fir tree transparent bud scale capsules

These are images of the bud "scale" capsule like coverings that are shed by the Abies nordmanniana (Nordman fir) in mid-late spring when the new needle like leaves begin to emerge. The scale coverings are thin and transparent and a shed almost as if they were thin egg shells.

Graveyard cypress trees - Cupressus sempervirens

By for the most common tree species in European cemeteries is the Mediterranean Cypress (Cupressus sempervirens). As a result it comes as no surprise that one of this tree species common names is "graveyard cypress". The connection between these tall upright Cypress trees (fastigiate crown) and graveyards is not a new. For several thousand years the Mediterranean cypress has been a symbol of mourning in the classical antiquity (Greece and Rome) and more recently in the Muslim world and in Europe. There are several factors that possibly contributed to this. One being the trees longevity, with it not being uncommon for the tree to live for 1,000 years. Another factor being the tall narrow shape as if the tree were pointing heavenward or as if it were standing guard over the tombs of the departed. The images in this post are from a cemetery in Spain.

Black locust - Robinia pseudoacacia

The Black locust tree (species name: Robinia pseudoacacia) is native to the southeastern United States but is widely planted in other regions as an urban ornamental tree. It is also grown as a honey plant in some countries.

The flower of the Black locust tree is a loose hanging "raceme" inflorescence. The individual flowers have a "papilionaceous" (butterfly like) shape (see image below). In Spain these flowers are sometimes called "pan y quesito" (bread and cheese) in reference to the fact that the flowers are edible. To give them a try all you have to do is pluck the petals from the flower base and nibble on the soft, sweet base of the petals. Some have even made a syrup from this sweet nectar.

The leaf arrangement of the Black locust tree is parallel, compound and odd-pinnate with the individual leaves having an "ovate" to slightly "obcordate" (heart) shape.

The Black locust is also a thorn tree although from my observations the twin thorns grow mainly on the "epicormic shoots". These are the shoots that grow from the base or trunk of the tree from an epicormic bud below the surface of the bark. The normal branches do not seem to have many thorns at all.

Olive flower inflorescence

The Olive tree´s flower structure (inflorescence) is an interesting example that illustrates the striking similarity between the branch structure and the inflorescence structure. Just like the arrangement of the leaves on the branch the flower structure is a branched "raceme" panicle that is both opposite an decusatte. There is one central peduncle (main supporting stalk of the inflorescenc) from which secondary peduncles branch out in opposite (two from each bract in opposing directions) and decusatte (each set of opposite secondary stalks are offset 90 degrees the the ones before and after on the main peduncle. Furthermore some of these secondary stalks are also branched opposite and decusatte with the pedicels (stalk of the flower itself). If this all sounds a bit confusing then just observe the images in this post and you will be able to see the similarity between the branch structure (bottom picture) and the flower structure.

Olive branch leaf arrangement

The Olive tree (species name: Olea europaea) has a leaf arrangement that is a good example of the "Opposite & Decusatte" arrangement. The "opposite" part refers to the leaves arranged in pairs that grow out of the opposite sides of the stem. The "decussate" part means that the leaves are arranged on a stem in opposite pairs at right angles to those above or below. The images below give a pretty good perspective on what this looks like. In the case of the Olive tree the leaves themselves have a narrow lanceolate shape with a short petiole. These pictures also show the new inflorescence forming right above the petiole on the new branch growth.

Cercis siliquastrum var Alba

The Cercis siliquastrum var alba is a cultivar of the European redbud tree species that has white flowers instead of the normal deep pink colored blossoms. Other than the color of the inflorescence there is not much difference to set this variety apart from the Cercis siliquastrum.

These images were taken in early April.

White mulberry spring flowers

The male flower of the White mulberry (Morus alba) is catkin like spike inflorescence. The flowers appear in mid spring from late March to mid-May (depending on your latitude).

As can be seen from the image below the male flowers appear on the tree before the new leaves.

below - new leaves on the male tree (male and female are separate trees)

The images above and below are of the flowers of the female White mulberry tree. The female flowers are shorter than their male counterparts.

Western hemlock tree

The Western hemlock tree featured in this post is from the Finch arboretum in Spokane Washington. The Western hemlock is one of the more common evergreen tree species in the Pacific Northwest. One way to tell this tree from other tree species in an evergreen forest is by observing the top of the tree. The Western hemlock, unlike other conifers, has a rather floppy top.