Botanical illustration: Mosses

Natural history illustration involves drawing subjects (like mosses!) that you’re not entirely confident about.  Recently I completed illustrations of two moss species for The Field Studies Council.

I was lucky enough to find both species growing on my local churchyard wall, but before drawing them I needed to revise my moss anatomy.

Many years ago I did a diagram of moss for The Amateur Naturalist by Nick Baker, so could refer to this.

Moss anatomy by Lizzie Harper, from “The Amateur Naturalist” by Nick Baker

Life cycle of Mosses: Gametophyte

Moss has a complex life cycle. It alternates generations between gamete and spore producing structures.  From greenish threads, a moss produces simple leaves and stems, attached with root-like rhizoids.  These structures are called gametophytes, and produce whorls of chlorophyll-producing leaves from a central stem.   The male and female reproductive structures are carried at the tip of gametophyte branches.

The male reproductive structures, (antheridium), produce mobile male gametes (antherozoids).  Antherozoids swim through moisture on the moss and fertilize the female organs, (archegonium). At the base of each archegonium, an ovary awaits fertilization.  Male gametes are attracted to the top of the structure with chemicals.  They swim down and fertilize the ovary.

Life cycle of Mosses: Sporophyte

The fertilized zygote grows from the parent, almost like a parasite.  It sends up a slender stalk which bears a spore capsule at its tip.  This whole structure is called the sporophyte. The spore capsule ripens, and when mature the cap of the capsule is shed.  Under this cap is a lid which splits away.  Beneath the lid (hope you’re following this mossy game of pass-the-parcel) is a set of teeth, arranged in a spiral or circular pattern.  Humidity alters the movement of these teeth, so when conditions are right they flick out the ripe spores.  These go on to germinate and produce a green thread-like mass, from which the new gametophyte grows.  Cycle complete.

Time to draw the pencil rough.

Illustrating Mosses

There were no sporophytes on my specimens, but luckily I had a decent field guide which allowed me to add them.  A great book on mosses is “Mosses and Liverworts of Britain and Ireland: A Field Guide” by Atherton, Bosanquet & Lawley

The client approved the rough.   I got out my hand lens and smallest paintbrush.  It was actually rather wonderful to get lost in the intricacies of the moss structure, painting as well as observing though my 10X lens.

Grimmia pulvinata and Tortula muralis

The finished result is something I’m pleased with.  I still have a long way to go before I reach the dizzy Bryological heights of expert moss illustrators like Christina Hart-Davies; but as one new to painting mosses it was a wonderful start.

Atrichum undulatum by Christina Hart-Davies

For much more on all things mossy, or bryological; please take a look at the website of the British Bryological Society