Saturday, April 2, 2022

Yet more catkins - but where is the frog spawn?

 There is still no frog spawn in my pond, though there was at this time in previous years, so I thought I would check out Loch Imrich and the marshy spot up Glen Banchor where there is usually lots of spawn.  None seen at all...

Going through the car park opposite the Balavil Hotel, I spotted some red catkins on the ground. They were rather like floppy caterpillars, and had some very sticky leaf buds at the end which had a strong smell. They smelled slightly sweet yet also a bit unpleasant.

Catkins and sticky leaves
The tree they fell from is a Western Balsam Poplar (Populus trichocarpa) which is native to Western North America but has been planted at the corner of the Balavil car park. If you walk past it later in the spring when the leaves are out, you you will notice the sweetish smell.
Western Balsam Poplar
This variety of tree is "dioecious" which means that the trees are either male or female and produce either catkins (if male) or flowers (if female). This tree must be male as it produces catkins, so sadly there will be no seeds. The catkins are rather beautiful in close up, being made up of lots of separate packets of pollen. UPDATE- see end of post to see what happened the next day!


 The Larch also produces red growths, but this time it is the female flowers that have the flashy ruby colour, and when pollinated will produce the cones.

Female Larch flower

The red colour does not last, but is easy to spot before the leaves come out. The Larch is one of the few cone bearing trees that lose their leaves in the winter. The leaf buds in the spring look like little green shaving brushes.

The photo above shows the female flowers having lost their red colour and starting to resemble the cones they will become. The male flowers are underneath.

This twig has last year's cones at the top

Most of the tall trees around Loch Imrich are larches so now is a good time to take a walk around and see if you can find the red flowers before they lose their colour.
UPDATE. I did this post on Saturday evening and when I came down on Sunday morning, the poplar catkin was surrounded by a pile of powdery pollen! So back to the microscope to see what was happening... (though this is actually easier with a x10 hand lens as you get a better 3D view)

The centre of the catkin goes down the middle of the photo and sticking out at right angles on each side  is a green-yellow plate or platform. The red bundles are supsended below the platform on tiny white stalks.

Each of the red bundles (probably the correct term is anthers) then splits and releases its pollen, seen as yellow grains.  There is a lot of it, as even from my sample there was a little heap of yellow powder around the catkin. Why so much? Well, this tree relies on the wind, rather than insects, to carry the pollen grains far and wide in the hope of landing upon a female flower of the same species. Unfortunately, this pollen may be doomed as there are no female Western Balsam Poplar trees anywhere in Newtonmore. Indeed, the nearest trees are recorded in Kincraig and I don't know whether they are male or female. I did go and have a look but they are still bare.
The map is from the BSBI database and each red square shows where a Western Balsam Poplar has been recorded.

Recorded distribution of Western Balsam Poplar 




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