Botanical illustration: Sedges Workshop

Story posted: Friday, 8. September 2017 by Lizzie Harper

In my career as a botanical illustrator, I sometimes come across whole groups of plants or animals that I know very little about.  The sedges fall into this category, a fact which became increasingly clear to me as I completed a whole swathe of these plants for the Field Studies Council’s leaflets.

I managed to complete the illustrations, although I found it tricky, but I decided then and there to back up this initial trial by fire by doing my best to learn a bit about these pretty plants.

Sedges workshop and sketchbook botanical illustration of sedges Carex by natural history illustrator Lizzie Harper

Glaucous sedge Carex flacca

Luckily, FSC has lots of diverse and fascinating courses on offer, including a one-day session learning about sedges.  (For more on another of these brilliant courses I attended earlier this year, please have a look at my blog on Learning about Slugs).

Our tutor was Mark Duffell, who, it turned out, was the same long-suffering botanist who’d advised me and helped me illustrate the sedges for the leaflets!  He was polite enough not to run screaming from the classroom, and was an excellent guide to the world of rushes, grasses, and sedges.

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Sketchbook illustration of Carex otrubae with hand lens and specimen of plant

We began by listing the uses of these plants, then learnt something of the main differences in anatomy between grasses, rushes and sedges.  There’s a handy rhyme here, pertaining to their stems:  “Sedges have edges, rushes are round, grasses have knees and are hollow down to the ground”.  Then, with the help of Sedges of the British Isles by Jermy, we started keying out a plethora of sedge specimens he’d brought in.

I have a habit of not working through keys, but rushing to the pictures and trying to match my plant to them; but this session changed my approach and in fact I was elated to key out six or seven sedges correctly.

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Sketchbook study of Carex demissa

One of the main distinguishing features of sedges is their stems; these are solid (not hollow) and mostly triangular.  They have ligules, like grasses, but these little flaps on each leaf near the stem tend to be firmly flattened to the leaf blade.  In grasses these are like collars extending from the leaves around the stem.  Sedges tend to grow in tufts or along runners of rhizomes; figuring out which growth habit your specimen has is vital.

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Sketchbook study of Carex sylvatica Wood sedge

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Finished illustration of Wood sedge Carex sylvatica

The reproductive region of the sedge, or flower, is called a spikelet and has all sorts of sedge-specific characteristics.  One of the vital structures to get your head around is the utricle, the female flower part which mostly surrounds the nut.  These utricles vary in size, colour, texture, and shape.  This was really clear from our observations.  Some have little beaks at their tips, some are shiny and green, others black and textured like suede, some have papery wings on their edges whilst others do not.

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Carex otrubae utricle (photo taken through the dissecting microscope)

A big indicator of species with the sedges is the number of stigmas the female flower produces; it’s either 2 or 3.  Mark told us a cunning trick to tell this when the stigmas had fallen off post flowering, generally the rounder and less flattened the utricle, the more likely it is to have three not two stigmas.

Another crucial structure is the glume, which surrounds male and female flowers and is papery thin, varying in shape and colour from species to species.  The details I tried to include in each of my sketchbook studies were therefore the ligule, the utricle, details of stigma number, and the glume.

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Sketchbook study of Carex flacca

It was remarkable how very different these plants looked, it was only on close examination that you could be sure they were all sedges.

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Sketchbook study of Isolepis cernua

Mark did a great job with his specimens and brought in some spike rushes (a sedge, but slightly different to the large Carex group, see the sketch above), and pointed out that cotton-grass are also sedges.

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Another Spike rush species, the Few flowered Spike rush Eleocharis quinqueflora

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Common Cottongrass Eriophorum angustifolium

By the end of the day I felt really happy using the sedges key (taken from the Sedges book by Jermy), and far more comfortable working and looking at the defining features of the sedge family.  Next time I get asked to draw sedges, I’ll have some hope of doing these fabulous plants justice!

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Sketchbook study of Carnation sedge Carex panicea

Sedges Grasses and rushes Carex FSC workshop attended by Lizzie Harper Botanical illustrator and natural history illustrator

Carnation sedge Carex panicea from the FSC Heathlands leaflet

 

 

On another topic entirely, I'm afraid I've had to turn off the "comments" button on my blogs due to spamming.  If you would like to give any comments or feedback, please do so on my Facebook page or Twitter account or email me at info@lizzieharper.co.uk.  Many many thanks; and apologies.

 

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