Back to Basics: The Basal Angiosperms

Darwin's 'abominable mystery’ describes the rapid expansion of the Angiosperms seen in the fossil record. The event conflicted with Darwin's belief that evolution was slow and gradual, and the massive expansion event of flowering plants across the globe puzzled him. 

Fig. 1 Expansion of the Angiosperms (purple) from 120 Ma

The Angiosperms are the most successful lineage of Land Plants, with around 400,000 species in almost all habitats. Their massive expansion came about during the Lower Cretaceous, around 120 Million years ago (Ma) (Fig. 1).

But where did they come from?

The closest living ancestor of all angiosperms has been a controversial topic for many years, with many different plant groups suggested as the top contenders.

In the late 1990s, the Angiosperm Phylogeny Group (APG), a huge collaboration of many scientists across the globe, worked to reveal the relationship of the majority of the Flowering Plant Families (i.e. Angiosperms) by sequencing certain genes from many different plants. This revealed that one species named Amborella (which only occurs in New Caledonia, Australia) is sister to all Angiosperms, and therefore most closely related to the ancestor of all Angiosperms.

Fig. 2 Basic evolutionary tree of Angiosperms. The basal Angiosperms include the ANA clade in the red box.

The Order Nymphaeales is thought to be the next closely related group of plants to Amborella. These two taxa, plus another order with the lovely name Austrobaileyales (say that after a few drinks!) from what is know as the ANA clade.

Although we don’t have Amborella or the Austrobaileyales in Ireland, we are privileged to have two species of the family Nymphaeaceae (within the Nymphaeales). There are only 50 species of belonging to this family, but they have managed to spread themselves around, and are found in many water systems. 

Distribution of Nymphaea alba 
in the British Isles

Nymphaea alba flowers and leaves
commons.wikipedia.org

The species found in Ireland are Nymphaea alba and Nuphar lutea, also known as water-lillies. Both of our native water-lilies inhabit still, clean water, and are easily recognizable by their floating, peltate leaves, and their beautiful, large flowers which can be seen from May to July.

Nymphaea alba (Bacán bán) named for its pure white flowers, is widespread all over Europe, and within Ireland they are more commonly found in the West. . The long stalks that hold up the peltate leaf blade is not a stem, but the pedicel of the leaf. The plants are anchored to the mud by the stem which lies horizontal on the bottom, and have many adventitious roots that penetrate the mud, holding the stem in place.

Distribution of Nuphar lutea
in the British Isles

Nuphar lutea flower
and leaves.
commons.wikipedia.org

Nuphar lutea (Cabhán abhann) or the yellow water-lily, is much more widespread globally, as it can be found in the temperate parts of the Northern Hemisphere.
In Ireland they are frequent from Lough Neagh in Northern Ireland down to County Clare, but rarer in the South and East Ireland. Apart from the yellow flower heads, these plants are distinguishable from Nymphaea as their flowers are on elongated peduncles that stick out, away from the water surface. 

A family that is quite rare in Ireland is Ceratophyllaceae, aka the Hornworts. Although they are not part of the Nymphaeales, or even the ANA clade, I find them interesting as they seem to cause a bit of trouble with many taxonomists. 

In APG III (2009) they state that 'the molecular evidence that Ceratophyllaceae are sister to the eudicots is becoming clearer', but 'they are morphologically divergent from their putative closest relatives'. The reason I have put them in with this post is because they are basal, aquatic, like our water-lilies, but also because they are very rare.

Ceratophyllum demersum. Image from
http://www.biolib.cz/en/taxonimage/id65312/

Ireland has two species: Ceratophyllum demersum which has only been recorded less than 15 times over the last 10 years. Although it is rare in the British Isles, it has become a major invasive species in New Zealand.

C. submersum has only been recently recorded in two locations in Ireland, once in Co. Down and once in Co. Wexford. It may be overlooked elsewhere, so get a-lookin' in some pools! 

The Irish Flora Blog

That’s right; another New Year’s resolution blog. Admittedly, I am over a month late getting started, but let’s not get into excuses.

I’ll be blunt and to the point: this blog is about plants. Yes, perhaps this is a dry topic for some (maybe many), but I hope to change minds into thinking more about how important plants are.

But before I get into that, a mini bio about me: My name is Hannah, I am a student of Botany for the last 3 and half years (maybe a bit more, I don’t know when to start counting); originally I studied in Galway, Ireland, and currently I am in Edinburgh, Scotland. I think I know a little bit about some stuff now.

I wanted to write this blog for 5 reasons. Bear with me.

1.       I think plants are fantastic, and sadly, under-appreciated. For a while I have been thinking it would be a nice thing to share some thoughts on why they are great to inspire some sort of appreciation for them in other people.

2.       I have come to realise over the past 3 years of studying Botany that there is an awful lot of jargon and mumbo-jumbo that could put off the most enthused student. I’ll try to sort that out for those who don’t know where to start when trying to puzzle this stuff out

3.       To find out more about the Irish flora, because that’s where I am from, and I think it’s got a lot to tell. A lot of us can appreciate how beautiful the Irish landscape is but maybe you never knew you were looking at plants when you watch the Discover Ireland ads.  I also hope that a lot of what I write is applicable to plants all over the world, mostly because Ireland doesn't have any unique plants so what you see here, you’ll find in other countries. This overarching theme will also help to focus what I want to talk about, as Botany is a huge subject, and I wouldn't know where to start otherwise.

4.       The Galway Botanic Garden Project. A bunch of enthusiastic plant nerds, plus myself, all of whom are from Galway want to create a Botanic Garden. This is a huge endeavour for us, and we would love if other people would like this happen too. So hopefully those of you who have gotten this far will want to be as excited about plants as we are and support us in our mission. Here is our little facebook page, please come say hi. 

5.       Lastly, I am writing this for myself. I have primarily been educated to think as a scientist, which involves a lot of technical writing and referencing and researching. I haven’t written anything for fun since I was in school. Overall I thought this endeavour would be a good opportunity to improve my writing skills, spread the good news, and potentially learn a lot.

What exactly is going to be in this blog?

I will attempt to write about the taxonomy, ecology, etymology, and stories of the Irish Flora, with some explanations about some hard words e.g. wtf is a ligule?, and why some hard words kinda mean the same thing e.g do roots=rhizomes?, and explain some tricky plant parts (perhaps with diagrams). In a broader sense, I will try to write a bit about what I know about the world of plants. Maybe you will find this useful. Maybe you won't. 

So here it is, my first botany blog post with, ironically, no plants in it. So here is a picture of one of my favourite plants, cause it's pretty. 

Centaurea scabiosa, which can be found in dry, calcareous (i.e. limestome) grasslands.

Disclaimer: I do not know everything, and therefore I may be wrong sometimes. If you spot a mistake please tell me, whether it be grammar or science. I am here to learn too. 

Note: You may have noticed I have not said how regularly I will be posting. This is intentional, as schedules are too real for the internetland.