The Tasmanian Blue Gum (Eucalyptus globulus Labil.) is a large tree species native to southern Australia. It also goes by the common names Southern Blue Gum and Blue Gum Eucalyptus. The tree in the image above is located in a botanical garden in Malaga, Spain. I measured the trunk of this tree at 1.6 meters wide at the base. This Eucalyptus tree species is one of the most common in Spain. The Tasmanian Blue Gum was "discovered" and introduced to the world by Citizen Labillardière in 1792. This was the tree species by which the Eucalyptus genus became known to the world.
The "fruits" of the Tasmanian Blue Gum are fairly large as far as Gum trees go. The tape measure in the image above is in centimeters and as you can see these woody, button shaped fruits measure about 2-3 cm across and 1-1.5 deep. The star shaped openings on the front are valves that release the seeds. In this picture you can see that the number of valves can vary (from three to six are possible). The "globulus" part of the Latin species name comes from the "small button" shape of the fruits.
One interesting aspect of this tree species is the pronounced difference between its juvenile, intermediate and adult leaves. The picture above shows a pair of new juvenile leaves that have formed on a new branch at the base of a large tree. In the image below you can see more juvenile leaves on another somewhat larger new stem.
In the next picture you can see how the secondary branches grow from the base of the juvenile leaves.
The picture below gives an idea of the difference in shape and size between the juvenile and adult leaves. you can also see that the adult leaves do not grow in pairs but rather are alternate.
The bark of the Tasmanian Blue Gum can be gray-blue or reddish and often has pronounced dimples on the larger trunks.
For more information on this tree species consult Eucalyptologics where you will find lots of information and resources on Eucalyptus cultivation around the world.