Christmas Bells

Christmas Bells
Christmas Bells - Blandfordia nobilis

Thursday, January 28, 2010

Eucryphia flowering in Robertson

Eucryphia moorei, or "Pinkwood" as it is known locally, is currently flowering in and around the village of Robertson. This plant has been adopted as the local floral emblem for several clubs and societies, as we are on the northern end of its range. Furthermore, the fact that in and around Robertson, it is growing on basalt soil here is of botanical interest, as it normally grows in moist soil, often basically a leaf-mold, over sandstone, in the wet gullies on cool, south-facing slopes of the Escarpment. So, the Eucryphias of Robertson are regarded as exceptional.

Out local Eucryphia is closely related to the "Tasmanian Leatherwood"(Eucryphia lucida), which is famous for the honey produced from it.

I know of numerous old trees which have "coppiced" - where the old original tree has died out and younger trees have grown from the roots of the original tree. As a result, these trees usually are found to be growing in a circle of trunks. This is commonly noticed in wet gullies.

There is one huge tree - the largest Eucryphia of which I know - growing as a free standing tree, with a massive trunk. It is growing on a private property at Knights Hill, on red basalt soil. It is unusual that this tree has survived a history of logging in the early days of European settlement in this district.
Rose and Carol posed underneath the tree
to provide a sense of scale of this massive tree.
Eucryphia leaves are located "opposite" to each other, and the next leaves appear at right angles to the last pair. The flowers are located in opposite pairs, coming from the leaf axil (emerging above the leaf).
Here is an individual leaf.
If you enlarge the image, you can see it has delicate hairs,
but, by contrast, the stem is markedly hairy.
the term for this is "tomentose"
"plant hairs that are bent and matted, forming a woolly coating".
Here you can see the buds forming in a tight cluster,
on the growth tips of the stem.
The buds at left and right are a matched pair.
The inner buds, also paired, at growing at right angles to the other buds,
as befits the "opposite" structure of leaves and buds.
According to the ANBG Website, the covered buds are
the source of the name Eucryphia:
-->- from the Greek "eu", well and "kryphia", cover, from the cap-like calyx. Here is a fresh flower, with the "calyptra" falling off.
The "calyptra" is a combination of the sepals (collectively called a calyx)
(protective sheath over the bud), which falls as the flower opens.
This sheath is noticeably sticky when the buds are developing.
That stickiness is most likely an insect protection
(much like a natural "fly paper").
The Eucryphia flower is the prettiest, purest flower.
The stamens radiate from the base.
The carpels are fused together in a central structure
which becomes the seed capsule once the flower is pollinated.
The style protrudes beyond the anthers, with pink stigma visible.
the function of the stigma is to receive the pollen
and to allow the pollen grains to grow down into the ovaries.
Here is a seed pod from last year's flower.
The style is persistent as a multi-pointed hard tip to the seed capsule.
Once again you can see the "tomentose" coating.
The seed capsule splits along the lines of the original carpel.
There are numerous "walls" (each called a "septum")
within the seed capsule.
When the seed is ripe, the capsule splits open along the lines of the "septa"
to release tiny winged seeds.
("septa" is merely the plural of "septum")

Botanically speaking Eucryphia is regarded as an ancient plant genus.

It has a "Gondwanan" distribution, with two species in South America (Chile and Argentina) and five in Australia.

Such a distribution pattern immediately tells you that these plants are of great antiquity - having formed into a recognisable genus while the giant supercontinent Gondwana was still a single unit. That means we are talking about period prior to the separation of Australia, Antarctica and South America.

Click here to view a computer generated graphic of the drift of the continents.

According to the geologists, Australia and South America were on opposite sides of Gondwana, but still fused together, at 200 million years ago. South America is believed to have split away some time before 60 million years ago. That dates the origin of Eucryphia genus at between 200 and 60 million years.

Eucryphias were regarded as belonging to a separate family (Eucryphiaceae), but recent classifications place them within the Cunoniaceae - along with the Coachwood, another dominant plant of the Robertson Cool Temperate Rainforest.


Russell Constable said...

Hey Denis that is one nice flower photo mate! One chunk of a tree too!nice post!

mick said...

A magnificent tree - especially the huge one you showed. The flower is beautiful and looks so delicate. Very interesting facts in your post.