P is for….Proteaceae

This is a group of plants very close to my heart. You could even say that I am addicted to them.

They have a huge Southern hemisphere distribution including South America, Africa, Madagascar, Australia, Indonesia and New Zealand. They are also very highly speciated with around 1700 different species among over 80 genera.

It comes as no surprise then that they have a fossil record that dates back all the way to the middle Cretaceous.

The earliest putative fossil record is dispersed pollen from (Late Cenomanian) Gabon in West Africa and has been assigned the name Trioris africaensis. It isn’t then until the Late Cretaceous (Santonian) that we find the first unequivocal proteaceous fossils in Australia. There are many species identified from fossil pollen found in the Otway basin, south eastern Australia. Some of these fossils are comparable to extant species. Macrofossils of the Proteaceae are less common, but are found. Of particular interest are leaves assigned to the extinct Banksieaephyllum and Banksieaeformis but also of the extant genera Banksia, and others, from Cenozoic Australia.

Many believe that the extinct and extant distribution of Proteaceae tell the story of how the ancient continent of Gondwana drifted apart. They do make a perfect example of Antarctic flora and their distribution has helped form the theory of continental drift. Not everyone is agreed on this though. Recent genetic evidence shows a close link between the Western Australian and Southern African species. Some believe this makes long distance seed dispersal an alternative force in their distribution and partially brings into question the mechanism by which they spread across the Southern Hemisphere.

They are represented in the fossil garden by species from South America, Africa, Australia and New Zealand and a walk around the garden to look at the species we have forms an interesting story of planet Earth’s prehistory.

Lomatia myricoides

 

Banksia ericifolia

 

Ephedra

I sit down to order some plants from Edrom Nursery in Scotland I am reminded that, for a while now, I have been promising a blog on a much overlooked genus of plants called Ephedra. Ben calls them the ‘green stick plants’ and they are just that; a bunch of green sticks growing out of a brown trunk. For most of the time that is.

Ephedra belong to an obscure group of plants called Gnetales, which includes plants such as Welwitschia mirabilis, whose leaves are potentially the longest in the world and a group of vines called Gnetum, the seeds of which are used as a spice.

So, what’s interesting about the Gnatales then?

Well, they are officially gymnosperms or non-flowering, seed bearing plants. Yet they have the same type of water transportation system as the flowering plants, Angiosperms. Not only that but they are insect pollinated just like the majority of modern flowering plants.

Ephedra-californica

Ephedra californica

Gnetales have had scientists quibbling over their relationship to other plants for a long time. Botanists can’t decide if the Gnetophytes should be sister to and thus separate from all other seed bearing plants, or sister to all other Gymnosperms, or sister to just the Pinaceae … or actually not a gymnosperm at all but sister to the Angiosperms. When you look at the fossil record of other, now extinct, seed bearing plants the phylogenetic relationships of the Gnetales become even more complicated. The debate continues!

Ephedrine, an extract of Ephedra, is a main constituent of the banned substance Chrystal meth and alongside a cocktail of other drugs was found in the blood of actor River Phoenix upon his death in 1993. Ephedrine is a regulated drug, yet Ephedra is still used in Chinese medicine and Mormon culture where it gets its common name, Mormon tea. It’s a stimulant and decongestant used in the treatment of Asthma, hay-fever and the common cold. The Mormons use it instead of caffeine since this is a banned substance in Mormon culture.

So how do these obscure plants fit into the fossil garden?

Well first of all, they have a fossil record heading all the way back in time to the Permian 290 million years ago. It’s not until the early Cretaceous, however, that fossils of Gnetophytes become more common. So they certainly fit the pre K-T extinction event theme we have going.

I can’t grow Gnetum gnemon outside here, it’s just too cold. Welwitschia may grow but so far I have had only limited success growing it from seed and certainly not enough success to try putting one in our ‘dry’ bed. Hence I am limited to Ephedra.

Welwitschia mirabilis at Kew

Welwitschia mirabilis at Kew

With a distribution that takes in southern Europe, Asia (including the Himalaya), the south western states of the USA and much of South America there are plenty of hardy species to choose from. With their small scale like ‘reduced’ leaves and twiggy sprawling habit, they are certainly untidy plants. They all need extremely free draining soils in the fullest sun that can be given so we have planted them amongst our Proteaceae, where they will hopefully make a matted understory to the more glamorous Banksias, Grevilleas and Proteas.

My hope is that they will come into their own when they ‘flower’ and eventually produce cones in shades through red and orange to pink and white. We have Ephedra nevadense, E. sinica, E. chilensis and are soon to have (I just ordered it from Edrom) E. gerardiana v. sikkimensis.

Ephedra chilensis

Ephedra chilensis

Alas, we have no room for more ‘green stick plants’, as they can become big and I am afraid that although they are intriguing in other ways, they certainly aren’t aesthetically interesting. Ben got quite bored while I dragged him around to look at the 8 species of Ephedra that grow in Israel. On a recent Australasian Plant Society trip to The National Botanic Gardens of Wales I got quite excited to see a huge plant of Ephedra chilensis. It suffices to say that not many others did.

Ephedra chilensis

Ephedra chilensis at the National Botanic Garden of Wales

Maybe beauty is in the eye of the beholder when it comes to Gnetales?