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Tuesday, June 29, 2010

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



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


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....

Sunday, June 20, 2010

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.

Monday, June 14, 2010

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 .

Thursday, June 3, 2010

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.

Monday, May 31, 2010

Cobaea scandens, Cup-and-Saucer Vine


A packet of seeds is still one of the best bargains around and you can germinate, grow and flower this tropical vine - the cup-and-saucer vine Cobaea scandens - in a single season, although in its native tropical America it grows as a perennial. In the UK you can grow it outside against a sunny wall, but it flowers more reliably in a conservatory, where it will quickly climb to the roof, clinging on with slender tendrils.

It's pollinated by bats and at dusk - at about the time that bats would emerge - the flowers emit a musty scen that attracts them. The bats visit for nectar but as they probe the flower those protruding stamens dust their furry chests with pollen that they transport from plant to plant. Cobaea pollen grains have an extraordinarily beautiful pattern of hexagons and pores on their surface when viewed under the microscope.


Pancrace Bessa, Flore des Jardiniers, 1836

Wednesday, May 26, 2010

Eschscholtzia californica, Californian Poppy


Easier to grow than to spell, Eschscholtzia californica, the state flower of California, is the botanical visual equivalent of a perfect, sunny-side-up egg yolk.... and there is an indirect link between orange flowers like this and egg yolks.

Birds can't make the yellow cartenoid pigment that's a component of petal colour in California poppy and many other yellow-flowered plants, so all the yellow pigment in birds' plumage and egg yolks has to come directly from the plant food that they eat, or indirectly from animals that they eat that have in turn eaten plants with the yellow pigment. For example, blue tits that have eaten caterpillars that have eaten plants deposit the yellow pigment in their breast feathers - so a blue tit that has bright yellow feathers is likely to be a good caterpillar hunter. It has been know for poultry farmers to feed orange marigold petals to hens so that they produce eggs with more intensely yellow yolks.  

Mammals can't make carotenoids either so plant carotenoids are the source of vitamin A which is a vital human visual pigment, which is why carotenoids have been genetically engineered into Golden Rice, to help prevent blindness in communities that have low levels of vitamin A in their diet.



Aside from its glorious golden flower colour, California poppy has very attractive glaucous green, feathery  foliage. I grew it in my garden last year and was delighted to find that it had self-seeded and that they seeds had survived our recent hard winter. Little glaucous green seedlings are coming up all over the garden.

Thursday, May 20, 2010

Dandelion, Taraxacum officinale


Even digital botanic gardens have weeds - in the case of mine, dandelions Taraxacum officinale agg. Dandelions are cosmopolitan weeds and long ago the European species was introduced into the United States, where it has become a major weed. Part of this plant's success can be attributed to its reproductive system, where it sets seed without the need for pollination, and its prolific seed production is coupled to an extremely effective wind-assisted seed dispersal mechanism. Back in 2007 two researchers at Purdue University in Indiana, Tamara McPeek and Xianzhong Wang, were curious to know how this plant might fare in future world where carbon dixide levels were double those of today - which is likely to occur around 2080. For the grandchildren of today's gardeners, their findings make ominous reading. The plants produced 83% more inflorescences and 32% more seeds that were larger, germinated better and established faster. Not only that, but they travelled further because their parachute of hairs (the pappus) was larger and carried the seeds further on the wind. Source: Tamara McPeek and Xianzhong Wang (2007) Reproduction of Dandelion (Taraxacum officinale) in a higher CO2 environment. WEED SCIENCE Volume: 55 Issue: 4 Pages: 334-340