Digitalis purpurea Foxglove

The use of foxglove Digitalis purpurea in herbal medicine was described long ago by Greek and Roman herbalists but the scientific investigation of its medicinal properties really began with the investigations carried out by the English botanist and physician William Withering (1741-1799).

Image source: http://en.wikipedia.org/wiki/File:William_Withering.jpg

William Withering was an outstanding botanist and in 1776 published his Botanical Arrangement of All the Vegetables Naturally Growing in Great Britain, a descriptive flora based on Linnaeus's new-fangled system of classifying plants according to the number and disposition of their sexual organs and reducing their Latin names to simple binomials - like Digitalis purpurea. Double-click on the image above and you'll see from the title page that this was an encyclopaedic botanical treatise, covering everything from preparing pressed herbarium specimens to the use of wild plants in herbal medicine, and it's in this book that he first mentions his interest in foxglove: "A dram of it taken inwardly excites violent vomiting." he wrote, " It is certainly a very active medicine, and merits more attention than modern practice bestows upon it."
The story is that the plant caught his attention when a 'wise woman' herbalist introduced him to an infusion of about 20 herbs that she used to treat dropsy (fluid retention caused by congestive heart failure). Withering surmised that the active ingredient was foxglove, that strenthened heart beat and acted as a diuretic, and in 1785 published An Account of the Foxglove and some of its Medical Uses, describing case studies - effectively clinical trials - of  patients who he had treated with foxglove.  The following is a typical example:

CASE XX.

January 1st. Mr. H——. Hydrops Pectoris; legs and thighs prodigiously anasarcous; a very distressing sense of fulness and tightness across his stomach; urine in small quantity; pulse intermitting; breath very short.[26]
He had taken various medicines, and been blistered, but without relief. His complaints continuing to increase, I directed an infusion of Digitalis, which made him very sick; acted powerfully as a diuretic, and removed all his symptoms.

Stately spires of foxglove flowers, usually growing best on acid soils, are a major attraction for bumblebees in June and early July.

When the bee forces its way in to reach the nectar at the base of the corolla tube its back is dusted with pollen from the yellow stamens positioned overhead. The stigma matures later, in the same position, collecting pollen from bees as they arrive from other foxglove plants.

 

 

There's no doubt that the positioning of the stigma and stamens and the bell-shape of each flower is an adaptation to cross pollination by bumblebees but the shape of the tubular petal has another role - keeping raindrops from the pollen on wet summer days.

Henbane Hyoscyamus niger

Henbane Hyoscyamus niger is a poisonous member of the potato family and has a long history of use by murderers. Its gruesome history, sombre colours and veined petals give it an aura of menace. It's reputed (controversially) to be the poison used by Hamlet's uncle to poison the prince's father, by pouring it in his ear, in Shakespeare's tragedy Hamlet.

Sleeping within mine orchard,

My custom always in the afternoon,

Upon my secure hour thy uncle stole,
With juice of cursed hebona [henbane] in a vial,
And in the porches of mine ears did pour
The leperous distilment; whose effect
Holds such as enmity with blood of man
That swift as quicksilver it courses through
The natural gates and alleys of the body,
And with a sudden vigour it doth posset
And curd, like eager droppings into milk,
The thin and wholesome blood: so dit it mine:
And a most instant tetter bark’d about,
Most lazar-like, with vile and loathsome crust,
All my smooth body.


More recently Hawley Harvey Crippen is reputed to have used it to kill his wife Cora in a notorious case in 1910, when the new-fangled wireless telegraph was used to aid the interception of the fugitive as he fled to Canada.

Like so many plant poisons, the toxic alkaloids found in henbane have medicinal applications and were once used as a hazardous anaesthetic by dentists. The herbalist John Gerard left a graphic account of their use in his herbal of 1597.

“Henbane", he wrote, " causeth drowsinesse, and mitigateth all kinde of paine… ………the leaves, seed, and juice taken inwardly cause an unquiet sleep like unto the sleep of drunkennesse, which continueth long, and is deadly to the party.
The seed is used by Mountibank tooth-drawers which run about the country, to cause worms to come forth of the teeth, by burning it in a chafing dish of coles, the party holding his mouth over the fume thereof: but some crafty companions to gain money convey small lute-strings into the water, persuading the patient, that those small creepers came out of his mouth or other parts which he intended to ease.”

In 2008 celebrity chef Anthony Worrall Thompson confused the poisonous henbane for the edible weed fat hen and published a recipe for its use in salads – a lurid example of the dangers of only knowing common colloquial names for plants rather than identifying them by their scientific names. No one is known to have suffered illness from the chef’s error, perhaps because henbane is not a common wild plant, and the chef didn’t seem to be too perturbed by his mistake. "I was thinking of a wild plant with a similar name, not this herb. It's a bit embarrassing, but there have been no reports of any casualties. Please do pass on my apologies", was his comment.

Franz Eugen Köhler, Köhler's Medizinal-Pflanzen 1897

Image Source: http://upload.wikimedia.org/wikipedia/commons/6/66/Koeh-073.jpg

Inula hookeri

This shaggy member of the daisy family, with its beautifully geometric spiral pattern of unopened central florets, originates from the Himalayas. In my garden it's a great attraction to bees, that appreciate the long period of pollen production that results from the sequential opening of all those florets.

I've been teaching botany since 1975 and over the last decade it seems to me that students have become increasingly frightened of Latin names. Maybe it's the purported British reluctance to learn languages, maybe it's because these days they see fewer plants in the field, which is the best place to associate a plant with its scientific name. Whatever the reason, it's a pity because Latin names often tell you so much about an organism and the people or places that are associated with it.

This plant's specific name commemorates Sir Joseph Hooker, who found it in the Himalayas and introduced it to British gardens in 1849. Joseph Dalton Hooker, one of the most eminent botanists and explorers of his day, laid the foundations for botanical biogeography and became Charles Darwin's closest friend and confidante, as well as serving as Director of the Royal Botanical Gardens, Kew for two decades.

Joseph Dalton Hooker

Image source: http://upload.wikimedia.org/wikipedia/commons/e/e9/J.D._Hooker-72.jpg

Sir Joseph Dalton Hooker has his own posthumous web site, created by Jim Endersby at the University of Sussex, for all those who appreciate the scientific achievements of one of the greatest of all botanists.

The generic name of this plant, Inula, has given its name to the carbohydrate inulin, which it stores in its roots instead of starch. Inulin - which is also present in Dahlia and Jerusalen artichoke tubers - has little effect on blood sugar levels and so is often used as a sweetener in foods for diabetics. Unfortunately - as anyone who has ever eaten significant quantities of Jerusalem artichoke will testify - it can generate acute attacks of flatulence for anyone who doesn't gradually add it to their diet.

Students often complain that Latin names are hard to remember. They're not when you decode them, when every name tells a story. Just remember to associate this flower with flatulence and Darwin's best mate and you'll never forget it...

Peony, Paeonia lactiflora

I'm not usually a great fan of double flowers but I do admire peonies and these two double-flowered varieties are so completely, excessively over-the-top in the multplicity of their petals that they have a particular charm. This one, Bowl-of-Beauty, puts me in mind of some elaborate ice cream confection served up at the seaside; a knickerbocker glory of a flower. Those white writhing filaments in the centre of the flower are mutated stamens.

I'm not certain which cultivar this one is because it had lost its label by the time I rescued it from the bargain reduced price section of a garden centre at the end of the season, with just a solitary leaf left to identified it as a peony. It cost me 50p. I think it's called 'Sarah Bernhardt', a cultivar that's been around since 1906 and an exotic flower for a very exotic actress. It looks as Parisienne as a can-can dancer's underskirts, with its endless tiers of petals.

Here is the lady in question, romantically portrayed by the photographer Nadar

Image source: http://upload.wikimedia.org/wikipedia/commons/3/3c/Sarah_Bernhardt-Nadar.jpg

... and here's a later studio portrait, showing that she liked flowers (although her corsage looks as though it's composed of Bourbon roses).

(Image source:http://en.wikipedia.org/wiki/File:SarahBernhardt.png)

Most peonies have a short but spectacular flowering period.  Paeonia lactiflora was introduced from China in 1784 and is extremely hardy. By Victorian and Edwardian times scores of cultivars had been bred and it became immensely popular. I have only ever tried growing peonies from seed once, an attempt that ended in ignominious failure. After waiting 18 months for seed to germinate I tipped them out of the pot, without realising that they produce fragile fleshy roots before any sign of a shoot appears. They had all germinated but every single root snapped in half. It was a good way to learn that patience is a virtue, but I still kick myself for it....

Fire or Bush Lily, Clivia miniata

It has always seemed to me that flower buds are some of the most remarkable natural objects- the botanical equivalent of a firework - containing the prepackaged, intricate beauty of a floral display just waiting to explode.............. and when it's a Clivia bud, the display can be truely impressive... 

Clivia miniata hails from Kwazulu-Natal in South Africa, where it grows in dappled shade in woodlands - and so it's well adapted to life as a houseplant, in shady rooms. Scores of cultivars have been bred and it's not a difficult plant to raise from seed. I germinated a batch of seed that I collected when I self-pollinated the plant in the photograph above and most flowered within four years of germination, producing a remarkably variable batch of seedlings. Sadly, none was better than the parent plant and several produced very small flowers. 

The name of this genus has its roots in Britain's imperial past and commemorates Lady Clive, Duchess of Northumberland and grand-daughter of the famous General Clive of India. The genus has a society dedicated to it - the Clivia Society - with an interesting web site.

Aloe variegata, Partridge-breasted Aloe

To mark the beginning of the football World Cup in South Africa, here's a familiar South African succulent species - the partridge-breasted aloe, Aloe variegata, that's widely grown as a houseplant here in Britain. I assume the common name comes from the  similarities in pattern between those beautifully variegated leaves and a bird's breast feathers, but the more direct connection between aloes and birds relates to their flowers. Like many red-flowered plants these aloes are often pollinated by birds - usually sugarbirds, which occupy the pollination niche that's filled by hummingbirds in the New World, but without their aerial agility. They are both after the same reward though - nectar, which is secreted inside those tubular flowers. You can find a guide to Aloe species here .

Brassica oleracea cv. botrytis, Romanesco broccoli

I have to admit that I'm not a huge fan of broccoli as a vegetable to eat,  but nothing comes close to Romanesco broccoli - in my estimation - as an vegetable to just look at. The geometrical precision of the curd, which is a mutant inflorescence made up of repeated spirals of flower buds, most of which never open, is almost hypnotic if you stare at it for long enough (especially if you've had a glass or two of wine beforehand). If you dissect one of these flower heads you soon discover that the pattern of spirals, so obvious in the whole structure, is repeated in the individual florets and again in the sub-florets (double-click on the picture for a larger image that makes this more apparent). This is what mathematicians call a fractal - each constituent part is a subset of the whole. This isn't the only plant to conform to fractal geometry - fern fronds follow the same mathematical logic.

The curds of cauliflowers and broccoli, which are naturally mutated inflorescences, are composed of buds that have proliferated to such an extent that they tend to rot away before they can flower. When I was a young postgraduate student I worked in a vegetable research station where new varieties of cauliflower were bred and was taught the technique of producing cauliflower flowers, so that they could be cross pollinated. The trick was to dissect a cauliflower into its individual flowers (scions) and to graft each of these onto a well developed decapitated cabbage seedling as a stock. Once stock and scion had united  the relatively small number of buds in the dissected piece of curd would flower and the flowers could be cross pollinated. So next time you are tucking into cauliflower cheese, spare a though for the horticultural skills of the plant breeders who bred your cauliflower. GM technology may be clever and sophisticated, but greenfingers are still sometimes needed in crop breeding.