Friday, 25 December 2015

Merry Christmas botanists!

BSBI President John Faulkner sends seasonal greetings to all botanists! 

Our Christmas present to you all - prompted by John's recent trip to buy a Christmas tree - is this reminder of how to tell which genus your tree belongs to. And a wince-inducing mnemonic to help you remember which is which.


John Faulkner with Lodgepole Pine & Nordmann Fir
Image courtesy of J. Faulkner
Trees courtesy of Benny Martin & Son,
Charlemont, Co. Armagh, Northern Ireland.  
The tree on the left of the photo is a Lodgepole pine Pinus contorta. The genus Pinus has needle-like leaves in clusters of 2, 3 or 5. 

The tree on the right of the photo is a Nordmann Fir Abies nordmanniana

It's fairly straightforward to separate Abies from Pinus, because Abies has leaves arranged singly along the twig, rather than in clusters.

But Abies can easily be confused with Picea, which also has leaves arranged singly along the twig - and Norway Spruce Picea abies is a very popular choice for a Christmas tree. Maybe this is why they had all sold out when John headed out to buy one! Twitter botanist Lophophanes tells us that Abies keeps its needles better than Picea but is more expensive to grow.

A good way to separate Abies and Picea is to stroke your tree, especially the twigs. You should be able to get away with such behaviour on Christmas Day! Do your twigs have peg-like projections or are they smooth to the touch?

Picea has Pegs Poking out. Abies 'Asn't Any At All.

After that low point, your day can only improve - have a great Christmas and remember to stroke a tree!