Monthly Archives: August 2017


Linnaeus, Erasmus Darwin, and the Canna lily

There are plenty of figures I admire in the history of botany, but there are two whom I can’t help liking as well. They are Carl Linnaeus (1707-1778), and Erasmus Darwin (1731-1802), the grandfather of the more famous Charles. Both had enormous and infectious enthusiasm for botany and all the sciences, and both were great communicators: Linnaeus enjoyed teaching and was well loved by his students; Darwin set himself the challenge of popularising in exuberant poetry the classification system of Linnaeus. He was also a leading light in the Lunar Society, a group which included amateurs like himself, industrialists such as Josiah Wedgwood and Matthew Boulton, and scientists such as James Watt and Joseph Priestley.


Why write about them all of a sudden? Because the Canna lily is in flower in my garden (above). That may not seem to answer the question. I’ll explain.

Linnaeus is best remembered for having achieved the heroic task of renaming the natural world, giving each species a two-part name: the genus (which includes close relatives) and the species names – the second identifying the individual. But beyond that he wondered how to group all these genera into a larger structured order, and hit upon an idea introduced in 1717 by Sebastien Vaillant, botanist at the Jardin du Roi in Paris. Vaillant spiced up his lectures by talking of the sex life of flowers – the anthers being the males with their pollen, and the stigma and ovule being the females. Linnaeus realised that he could use this to classify plants by the number of stamens and stigmas borne by their flowers. He wrote:

‘The flowers’ leaves (n.b. = calyx and corolla) contribute nothing to generation, but only do service as a bridal bed, which the great Creator has so gloriously arranged, adorned with such noble bed curtains and perfumed with so many soft scents that the bridegroom with his bride might there celebrate with so much the greater solemnity. When now the bed is prepared, it is time for the bridegroom to embrace his beloved bride and offer her his gifts; I mean then one sees how the testicula open and powder the pulvarem genitalem, which falls upon the tubam and fertilises the ovarium’

(Praeludia Sponsaliarum Plantarum, 1729)

So far, so biologically correct. But anyone who has looked closely at a flower will have seen that the bed is often well populated, and in his great work Systema Naturae published in 1735 Linnaeus was forced to describe orders such as ‘Decendria: ten husbands in the same marriage’ i.e. a flower with ten stamens. The illicit thrill of plant sex may have contributed to the popularity of plant collecting in the eighteenth century, , but this scandalised many people and brought Linnaeus some scientific opposition.   Johann Siegesbeck, a St Petersburg academician, denounced Linnaeus’s ‘lewd’ system with its ‘loathsome harlotry’. Linnaeus had his revenge: he named an unpleasant small-flowered weed Sigesbeckia.


Linnaeus in his wedding portrait of 1739, seen holding a sprig of the species he named after himself – Linnaea borealis.

Yes, you say, but Canna lilies? Well, they are one of the few flowers to have a single anther and single stamen – the sparsely populated order Monandria Monogyna in Linnaeus’s system. When Linnaeus married, verse composed for the wedding portrayed him as a ‘monandrian lily’ – a Canna. So these flowers, often seen in municipal plantings, could be said to symbolise monogamy and fidelity.


Canna flower showing  the petal-like structures of the anther (the curl of yellow against the orange, on the right) and stigma (the curl on the left)

Monogamy was a fine theme for the devout Linnaeus, who married but once. By contrast the atheistical Erasmus Darwin sought the pleasures of life, siring twelve children by his two wives and a governess. Darwin was however an enthusiastic supporter of Linnaeus’s simplified system, and conceived what to us might seem a crazy challenge: to portray a system of scientific nomenclature in wild verse for which the only adjective has to be flowery.


Erasmus Darwin, by Joseph Wright of Derby, 1770

His The Loves of the Plants, published in 1784, begins with the Canna:

First the tall CANNA lifts his curled brow

Erect to heaven, and plights his nuptial vow;

The virtuous pair, in milder regions born,

Dread the rude blast of autumn’s icy morn;

Round the chill fair he folds his crimson vest,

And clasps the timorous beauty to his breast.

Well, you can see why Byron wrote of ‘Darwin’s pompous chime / That mighty master of unmeaning rhyme’.

Darwin, like Linnaeus, was also in error in assuming that it was the norm for flowers to be fertilised by pollen from their own anthers. In fact many plants have adaptations to favour cross-pollination, and it was Erasmus’s grandson Charles who wrote a book on how orchids in particular achieve this.

I recommend wholeheartedly the books which introduced me to this story: The Poet as Botanist by Molly Mahood, and The Lunar Men by Jenny Uglow.

Finding a jazz track with the theme of monogamy is almost as hard as finding one on botanical nomenclature, but here’s Charlie Haden with a tune he composed for his wife Ruth, played with Pat Metheny. (Ah, this doesn’t seem to be authorised anymore on WordPress, so look up Charlie Haden and First Song on youtube.)






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