Mosses and liverworts at Whitehill Wood

On the dry, early spring morning of 27 March, nineteen members gathered by the entrance to Whitehill Wood, near Stonesfield, to hear Peter Creed’s introduction to mosses and liverworts.

Peter told us about the two main types of moss: acrocarps which are tufted mosses and grow from a central point often forming circular cushions, and pleurocarps which have longer shoots and are more tendril-like, often with branches. 

We then followed the path between the river Evenlode on the left and a steep bank of woodland plants and trees on the right, stopping at intervals to look at some common species of moss, noting the differences between the two types, and the differences between mosses and liverworts. 

Lots of early spring flowers were seen including Wood Anemone, Moschatel (aka Town Hall Clocks), Lesser Celandine, and Common Dog-violet. Many of us were hoping to see the small Yellow Star of Bethlehem and we were in luck as about ten in total were seen. The star-like flowers of this plant are yellow with a green stripe on the outside of the six petals; it has a single blade-like leaf that rises directly from its base. 

In a few places, mainly on the river-side of the path, we saw a number of Toothworts. These are strange flowers which lack chlorophyll and so are completely unable to photosynthesize. They survive by being parasitical on the roots of Hazel and other trees. They have small pad-like suckers which attach to the roots of the host plant. These dissolve the tissue until the main feeding parts of the root are reached. The sap is then diverted from the root to the Toothwort. 

The most common plant in the wood is Dog’s Mercury – it carpets large parts of the woodland floor. It has a bad reputation as it’s poisonous and inhibits the growth of other plants. I hadn’t previously given it much thought. Peter explained that the plant is dioecious, which is a botanical term meaning there are separate male and female plants. This is unusual as most plants have both male and female flowers on them. We saw the different types of flowers on the Dog’s Mercury; on male plants they resemble yellow catkins and on females the plant develops small paired fleshy fruits. The spread of Dog’s Mercury by seed is very slow and the reason it is so abundant is that it spreads mostly by rhizomes, creating large single-sex patches on the woodland floor. 

Signs of various mammals were visible: tracks in the mud made by Muntjack and Roe deer, and badgers; fox scat and an otter slide and spraint, and also nibbled nuts. Our return was via Stonesfield Common where we enjoyed the views before heading back to our cars. A very informative and enjoyable morning spent with other budding bryologists. 

A full species list can be found here. See also.

Jonathan Noel 8 April 2022

Photographs by Jonathan Noel except Yellow Star of Bethlehem (JC)