A lockdown horticulture lesson here from Sarah Horton on the small wonders in our yards and pavements most of us probably never even notice. The tiny plants I’ve only called ‘weeds’ in the headline to get your attention. In fact, as you’ll hear from Sarah they’re not mere weeds for the clearing but complex and precious examples of life on earth.
One of the things we’ve all had to adjust to in the pandemic is the restrictions in our daily lives and on where we can go. So we’ve all spent a lot more time in our homes, and if we have one, our gardens.
Our garden isn’t really a garden at all but a small backyard, which is much loved. In fact, so loved we’ve realised during the lockdown that we don’t want to leave it and move to a flat overlooking Sefton Park, because that wouldn’t have our own outdoor space like this. The little yard is precious.
But the yard was never going to be big enough to satisfy my horticultural desires, so I got an allotment for that twenty years ago, another much loved piece of land which has featured in our pandemic stories of our lives. So our yard is a sitting space, an extension of our home rather than ‘a garden’. But out here even what we would have called ‘weeds’ are now in fact essential studies for me. For example, on my Identiplant course we’ve already done the cabbage family. Plenty of those grow in cracks on pavements and walls, and so we found all the species I needed on the walk around where we live in Home Life Week 1. We’re now doing the campion family and I’ve realised the ‘moss-like weed in the cracks’ in our yard is actually Sagina procumbens, or Procumbent Pearlwort, a member of the campion family.
Pearlwort is known as ‘a common weed’, meaning a successful plant. It is found throughout the Northern Hemisphere and in parts of South America. It is now growing on Gough Island in the South Atlantic where it has probably been introduced from visitors’ footwear… so a very successful plant! I’ve also done a very interesting webinar this week about ‘Polar Plants’ and Antarctic Pearlwort (Colobanthus quitensis) is one of only two native flowering plants in Antarctica. Since doing the Identiplant course and opening my eyes to finding wildflowers wherever I can, I’ve come to appreciate them, and also to notice more than the plants I am studying. So whilst looking for Pearlwort in our yard, I’ve also come across several colonies of these liverworts. Identifying this species as Marchantia polymorpha, although I am not an expert.
A liverwort is a non-vascular plant, known as a bryophyte, like mosses. Vascular plants have tissues that can move water and nutrients around the plant, but non-vascular plants are limited in size by poor transport methods for water, gases and other compounds. So, they are considered ‘primitive’, although I find the term to be unfitting given the complexity of their lifecycle. In the ’thallus’ seen here, the leafy base of the plant is several cells thick. The upper side is green and photosynthesises, and the underside has hair-like cells called rhizoids that absorb water and anchor the liverwort to the ground (so it does not have roots). They prefer moist habitats and reproduce via spores, rather than flowers and seeds.The umbrella-like structures seen here are ‘archegoniophores’, the female organ, which will be fertilised by sperm from a male organ. This develops into a sporophyte which produces spores which grow into a male or female thallus, and then the process begins again. The plant can also reproduce vegetatively as well. The spores it produces are coated with sporopollenin – this is one of the hardest known substances and prevents the spores drying out until the right conditions are found to begin reproducing. A researcher as Sheffield University has discovered spores which are 470 million years old. Which suggests that some of the earliest land plants were probably related to this liverwort. And that is truly amazing!
“For everything that lives is holy, life delights in life”William Blake
It’s quite wonderful to think all this life on earth has been going on in our back yard for over 25 years, and I’ve never noticed it all before!