30 November 2017

Tree Flowers: November 2017: Lime (Tilia Species)

Pollen deposits found from pre-historic lime blossom has revealed that the small-leaved lime was once the most common tree in lowland England. However this wasn't the case for long as the tree cannot produce fertile fruit below a mean average summer temperature of around 20 degree Celsius. This drop happened around 3000BC in England meaning that the lime tree was stuck wherever it had already occupied. These places became fewer as woodland was cleared and the lime was then used for coppicing.

Species of Tilia remain popular amenity trees, planted in many communal places, such as parks and tow roadside verges. We even have a circle of lime trees in a nearby housing estate.

There are three lime trees in Britain (often called Linden trees in other parts of the world), with the small-leaved and large-leaved lime being the parents of the fertile common lime. The large-leave lime remains quite a rarity, with the other two being much more common.

Lime trees can persist almost indefinitely via the wonders of coppicing, via which the tree provides 'bast' (the origin of names such as Bastwick in Norfolk), which is the inner bark from young poles for making rope and fabric fibres. But historically, the lime has also been used for wood carving.

Westonbirt Arboretum in England has a coppice of limes that has been estimated to be around 2000 years old and can be seen in the photo below.

But what I really like of the lime is the bract that hovers over the flowers making it clear to the world that it is, indeed, a lime tree.

The flowers mature at different times, so you'll be able to see buds as well as fully open flowers.

Each flower contains both the male and female parts, with the petals being a greeny-yellow colour. The flowers hang in clusters ranging in number from around 4 to 10. The pale filament provides a good contrast to the bright yellow anther, all of which surround a robust stigma.

Because the bract is so easy to see, even from a moving car, I enjoy looking for the flowers each year, which tend to arrive by mid-summer. I'm very much looking forward to observing the flowers again next year.

Mabey, R. (1996) Flora Britannica. 1st edition. London: Chatto & Windus / Sinclair Stevenson.
More, D. and White, J. (2012) Illustrated Trees of Britain and Northern Europe. London, UK: A&C Black.

24 November 2017

Book Review: Plants From Roots to Riches by Kathy Willis and Carolyn Fry

The book and accompanying radio series were produced at a time when funding was in doubt for Kew Gardens and this book serves as a reminder of, not only the deep history, but also the ongoing services that Kew provides in the realm of botany.

Some of the most important giants of British botany have been part of Kew, from Joseph Banks to the father and son, Hooker. The history of Kew is not just stored in the herbarium or in dusty books, but also in the form of Encephalartos altensteinii, the oldest pot plants in the world - arriving at Kew in 1775. This is important. This plant has been potted up and at Kew for around 20 years: making it a year older than the United States of America.

But Kew doesn't rely on history to keep its place. The scientific study of plants for economic reasons seems to have been a foundation stone. Kew, thoughout its history, has attracted the best scientists and plant hunters, and this has enabled Kew to be relevant not just today, but for an unlimited time in the future.

However, this isn't just a book about Kew. It is a book that delves into the worldwide history of botany. We read of heroic people starving to death in the Siege of Leningrad so that Hitler couldn't plunder the seed bank there. We read of the wonderful Beatrix Potter and her diagrams of fungi and of De Barry and his study of potato pathology. We hear of people that travelled the globe in search of plants that would not just provide a welcome sight and beauty for the eyes, but that would heal us (such as Cinchona), that would feed us (such as yams), and that would help us make products to enrich our lives (such as rubber).

Wonderfully written and well illustrated, this book was a joy to read. Broken down into bite size chapters that match the radio series, the rich content of this book does not overwhelm. I restricted myself to two chapters per day, so I'd have time to digest what I was reading - but could have easily read more!

I was hoping that the hardback version would be a lavish glossy book with all of those illustrations placed on the relevant page, but sadly, this doesn't seem to be the case. However, some illustrations are provided on the standard pages,but there appears to be no difference betweek hard and paperback versions.

The radio series is available for download from the BBC here both as individual episodes and 5 omnibus downloads. I read the paper copy that has 4 sections of plates for illustrations and photographs.

Well worth a read.