This year I am following an avenue of 100 disease-resistant elms, Ulmus ‘New Horizon’, in Pontcanna Fields, Cardiff.
When I visited just over a month ago there were little red flowers with no petals. Now these have disappeared and the trees are greening up with their pretty, slightly lopsided leaves.
These leaves are “alternate” (spiral, not exactly opposite each other), with simple, “doubly serrate” margins (meaning there are smaller serrations within the serrations), asymmetric at the base and “acuminate” (tapering) at the apex.
I must admit that I was so taken by the arrival of the leaves that I forgot to look for the fruits that had developed from last month’s flowers until I saw them through the camera lens and recognised the distinctive shape…
The fruit is a heart-shaped “samara” coloured with chlorophyll, meaning it can use photosynthesis even before the leaves sprout. The shape means that when it dries the wind can carry it farther away than a seed that just drops to the ground. I hope I don’t miss that time of year.
A samara is a simple dry fruit. It is formed from one carpel (female sex organ including the ovary) and the single seed nearly fills the pericarp shell around it, but doesn’t stick to it. The flattened wing of papery tissue develops from the ovary wall.
A samara is a sort of “achene”, from the Greek ἀ, meaning not, and χαίνειν (chainein), gaping. An achene is indehiscent, meaning it does’t open up to release the seed.
There are now flowers around the elms…
Thanks to John over at the “Rivendell” garden blog – the name made me think of Tolkien’s Lord of the Rings. I remembered an old painting of Lothlorien, realm of the Elves. It has nothing like the expanse and complexity of the movie version, but the image’s evenly spaced young trees remind me a little of the elm avenue…
I’m enjoying this! I hope you are enjoying your tree following, too.
Find out more about the 100 elms here.
Find out more about tree following here.