Some time back, I wrote a post on Sizing up the Syzygiums as a general guide to “leaf whispering” this large group of very similar looking species commonly called lillipies or satinashes.
After being able to look for certain spot characteristics such as flanging on the internodes (the stem sections between successive new leaf growth) and details of venations, it is possible to finally start seeing differences between different species of Syzygiums.
Yet some of the more common Syzygiums still occassionally stump me.
And here I am referring to Syzygium australe, Syzygium olesum and Syzygium smithii.
This is why:
They are all typically small trees to tall shrubs, have flanged stems, and elliptic to slightly obovate leaves. The leaves of theses species also tend to have depressed midribs. They are also sometimes found growing under similar conditions, such as along rainforest edges or in the eucalypt forest with rainforest understoreys.
Fortunately when flowering or fruiting they are quite distinct from one another, but the challenge is to be able to distinguish them when they are not in flower or fruit.
So lets begin.
Differences in stem flanging
Syzygium australe, the Creek Satinash, is probably one of the more common satinashes in the region. It is also widely grown in gardens. Among the three species, it has the most developed stem flanges, which in young shoots may have a slight red tinge.
S. australe and S. smithii have rather shiny bright green leaves, but in the field I have often observed that this sheen is brightest in S. australe. S. oleasum tends to have the darkest tone of green among the three
Visibility of oil dots
Also compared to S. smithii, S. australe has less visible oil dots when you hold the leaves up against the light.
The differences when the three are in flower are quite marked.
S. australe often has 3 flowers, but sometimes more. The flowers are quite large and showy (the stamens “explode” outwards giving the flower a bit of a pom-pom look). Syzygium oleosum has similar showy flowers, but the inforesences look somewhat more pendulous.
S. smithii is probably the most different from the two, with very small flowers and a much more complex branched inflorescence.
Smell of crushed leaves
Syzygium oleosum is instantly recognizable from the other two from the smell of the crushed leaves, which has a more turpentinish or peppery smell. In contrast, the crushed leaves of S. australe and S. smithii have a sweeter, milder scent.
It is probably worth noting that Syzygium australe can be quite variable as there appears to be quite a number of varieties of the species in cultivation.