hughcarter95's picture

Birch tree

Observed: 26th October 2009 By: hughcarter95hughcarter95’s reputation in Plants
IMG_1726
Description:
Identifications
Species interactions

No interactions present.

Species with which Downy Birch (Betula pubescens) interacts

Comments

Syrphus's picture

I have noticed that you have

I have noticed that you have posted a few records recently from N and W Scotland. I would like to add some of them to the HBRG database and NBN Gateway. Would you contact me on records@hbrg.org.uk to confirm your willingness and to have your name on the record as recorder?

Murdo

TRY

recording wildlife with The Recorder's Year on www.hbrg.org.uk/TRY.html.

Pieris's picture

Downy or silver

Just something I thought may be of interest:

From the stuff I've read, identification of pendula and pubescens is a largely theoretical exercise. There are many intermediate forms. Current thinking is that hybridisation between the two birches is rare and the intermediates are, genetically speaking, all pubescens...but it's not that simple.

Pendula is said to be diploid (two sets of chromosomes) while pubescens is tetraploid (four sets). Studies of some East Anglian birches show a strong correlation between diploid trees and pendula morphology. However, tetraploid birches can show the whole range of morphology, from "pure" pendula to "pure" pubescens. This obviously makes identification in the field difficult - that lovely silver birch could be concealing downy birch chromosomes.

To further muddy the waters, my Collins Tree Guide says of silver birch shoots: "Hairless (except for strong sprouts)."