h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

First of all: what is a succulent plant? Basically, it's a plant with some part of it that is thick and juicy - mostly, the stem or the leaves. These are for storing water, since most succulents experience dry conditions for a significant part of the year, and store up water when they can. I personally don't really consider plants to be succulent if they *only* have thick subterranean tubers. If a part of the tuber is exposed above ground then, yes, I consider it a succulent.

Succulents are not necessarily closely related to each. In South Africa (and elsewhere), a succulent condition has evolved in a great variety of plant species - in many different groups. There are some groups with only a few succulent species, and then some in which most or all species are succulent.

South Africa - actually, let's be more inclusive and talk about Southern Africa (and thus, including Namibia, Botswana, Zimbabwe and the southern part of Mozambique) has a great diversity of succulent species because:

1. It is drier than the tropical African areas to the north towards the equator, meaning, more plants have had to adapt to the dry conditions.

2. Most of Southern Africa is significantly cooler than the more tropical parts of Africa. For most succulents this means that adaptation to extreme heat has not been as much of a factor as it would have been in hotter regions. But we do have some very hot regions. At the same time we have regions with mild climate, and some that experience very cold winters. For instance the incredible Spiral Aloe is found in areas where it gets buried in snow in winter:

http://www.flickr.com/photos/brewbooks/184343789/

3. It is geologically complex, with mountains and rock formations of great antiquity. Plants evolve closely to adapt to specific kinds of soils. A big problem is mining - since, mines look for interesting minerals in high concentrations ... and those very high mineral concentrations often support plants that grow there and nowhere else.

4. Parts of it has been extremely stable - Africa as a whole is a very stable continent. Thus evolution has been going on uninterrupted for a very long time.

5. Parts of it has experienced significant climatic fluctuations. There have been repeated cycles of hotter/colder and/or moister/drier climates. Each time certain plants have adapted to the new conditions, becoming new species. In the Southwestern Cape this factor has worked along with the 'coincidence' that many mountain ranges have their main axes in a east/west direction. This means that there are northern slopes – hot, dry and sunny – and southern slopes – cool, moist and cloudy. As climates changed, plants could survive merely by switching from northern to southern slopes or vice versa, or traveling higher up the mountain (towards cooler locales) or lower down (towards warmer locales). This process didn’t mean that plants could stay the same – they did also evolve – but having suitable climates close by, saved many of them from extinction (which would have happened if they lost all areas of suitable climate) giving them more time to adapt. This has led in the southwestern Cape to one of the richest floras on Earth – of which succulents form a major component. The non-succulent flora is called Fynbos (fine bush) while the succulent flora of the Southwestern Cape is called the Succulent Karoo.

6. The Succulent Karoo, which is the region with by far the greatest succulent diversity, receives winter rainfall – softer rains, and more regular rains, than most other desert regions. This has allowed the evolution of a very large number of *small* succulents. The group that is most diverse here, is the Ice Plant Family – the Mesembryanthemaceae.

South African succulent vary from tiny to huge. The largest is the Baobab Tree! This is a giant succulent, storing water in its huge, fat trunk, which is composed of soft, fibrous pulp rather than wood. It can be many inches ‘thicker’ in a wet year than in a dry year, as a result of this water-storage capacity. The thickest Baobab in South Africa is about 15 m thick – more than 45 m in circumference. There are a few that achieve 10 m in trunk thickness, and many that exceed 5 m. They are usually rather ‘short’, not many exceeding 15 m in height – but some reach 25 m.

A nice photo here on a German site:

http://www.feierabend.de/Suedliches-Afrika/Pflanzenwelt/Baobab-26615.htm

On the other end of the size scale are succulents that are tiny – mere milimetres tall and/or wide. And even though our modern society so often emphasise and esteem things that are big, spectactular, etc. I’d for a while like to impress upon you just how delightful, wonderful and beautiful many of the *small* things are! So please check out these tiny but lovely little succulents:

First, Avonia, sometimes called ‘goose droppings’ – their little bodies, clad in miniature scale-like, white leaves, are mere millimeters in extent, and yet, they too are clearly succulent! An example are the pygmy Avonias at the University of the North – they survive in a ‘habitat’ that is a patch of grit a couple of feet wide and half an inch deep, on an exposed sandstone rock ‘monolith’, that in Summer gets baked by the sun hot enough to easily fry an egg on.

This photo is of a related species of Avonia – with a coin for scale:

http://plants-pottery-photo.blogspot.com/2009/06/avonia-alstonii-ssp-quinaria.html

Anacampseros is a related genus – most of which are also tiny, also preferring shallow pockets of grit:

http://www.succulent-plant.com/families/portulacaceae/p1010127.jpg

Crassula is a HUGE genus including mostly small species, but a few are large, two reaching what can be considered tree size. The small ones include many with lovely leaves and symmetric shapes:

Crassula marnieriana:

http://www.highsierranursery.com/Plant%20ID/Crassula%20marnieriana.htm

Crassula ‘Buddha’s Temple’ – hybrid of Crassula pyramidalis and Crassula perfoliata:

http://www.cactus-art.biz/catalog/product/2779/Crassula-cv.-BUDDHA'S-TEMPLE.asp

Crassula columnaris:

http://www.bidorbuy.co.za/item/24959421/VERY_RARE_Crassula_columnaris_ssp_prolifera_Seeds_Indigenous_Succulents.html

Conophytum includes a great diversity of species, but most with small, round bodies, from which pretty flowers emerge – flowers usually white, pink or yellow:

http://www.lithops.net/images/Mesemb_photos/Conominutum-nud5867.JPG

Right – I hope you could appreciate that! In my next installment I will speak of the ‘Big Five’ succulent families/grous of South Africa: The Aloes and their relatives; the Euphorbias; the Crassulas and their relatives; the Carrion Flowers; and the Mesembs (or Ice Plants).

Willem, no time to read or look at photos at the moment but I will be back when I get time.

Hope your Mom is



Websailor

Beautiful, Willem. The baobab, too? Who knew?

By the way, I find anti-hotlinking messages such as the one above extremely rude. Those who have objections to hotlinking should say so clearly, on the webpage.

<>

I don't know what that means, could you explain? I presume you didn't mean my post which is what I first thought

Websailor

I'm sorry, Websailor, I didn't mean you. If I click on one of those links, I get one of those messages:

'This person is trying to steal my bandwidth.'

Not only do you not get to see the picture, but you get an accusation of wrongdoing.

When we stick these links in our posts, it's called hotlinking. Some people object to this, because they have to pay if too many people click on their websites. So they don't like it if you only do it to see their pictures.

My objection to the anti-hotlinking messages is:

1. They're often rude.

2. The person could simply state that they don't want hotlinking, and then use a generic message - a friendly one, saying, please visit my website - to prevent his.

3. Often, the pictures they have on their websites have been 'borrowed' without legal permission or attribution from another website. Sometimes, they have even 'borrowed' music. (I don't know if that man paid a BMI fee for the music he added to his site. If he didn't, the fact that he played it on a MIDI doesn't make it legal.)

In these cases, I am sorely tempted to bookmark their site and visit it regularly, thus making it more expensive for them to do business. I don't do this, of course, but I am tempted.

That's very interesting. That has never happened to me and I didn't even know that was what it was called! Thanks for enlightening me.

Websailor

You're welcome.

Oops! I'm sorry about that link - I was in a hurry Saturday to get finished and didn't check if all the links worked. Try this link for a photo of an Anacampseros - and interestingly, this is the same one that occurs here around the Pietersburg environs:

http://www.ruhr-uni-bochum.de/boga/html/Anacampseros.lubbersii.ka1.jpg

I thought the internet was all *about* linking!

That's a strange plant, but pretty




Websailor

That one was worth waiting for. Very cool plant.

Lovely plants Willem! I hope your garden has recovered from the vandalism. What strikes me about that last plant is how large the blossoms are compared to the plant itself. I had no idea how varied succulents were, that the baobob tree was one as well. Thanks for the information.

Hi there folks! Yes Anacampseros plants have huge flowers relative to the rest of the plants. I love them! I really hope to soon get to taking some photos of my own plants. Right now I'm busy as heck just taking care of them - spring planting is hectic!

Elektra, my garden is recovering well. Sadly though the beautiful Aloe chabaudii plant didn't make it. But we got a few more of the same species from a local nursery and I planted them in the part of the garden inside the fence where they ought to be much safer. But it will take a year or more before they will flower.

This post has been removed.