Phenology epitomizes cryptogamic botany

Half the time you can’t see what you want to see and when you can see what you want to see you know you’ve missed what you wanted to see so you then have to wait another year

Introduction

The idea of a Phenology project was born during the Worcestershire Spring weekend meeting in 2023. Conversations with Jeff Duckett during the meeting revealed how little we really know about the reproductive life-cycles of even the commonest bryophytes. How long do capsules in different species take to develop from fertilisation to maturity (some take more than 12 months, as Jeff explained in his Spotlight article in November 2023)? Some species fruit just once a year; others can be found with capsules throughout the year, but do you know which?  Liverworts are even more of a mystery, as sporophyte development mostly occurs tucked away inside perianths: we have no idea when or if fertilisation has occurred unless we take the trouble to look inside a perianth under the microscope. Then, even when something does happen and the sporophyte emerges, it is usually only visible for a day or two and is easily missed.

The plan in outline

Jeff, Philippa and I (Claire) spent a couple of days in January 2024 looking at fruiting specimens in detail and discussing this as a potential project. It soon became clear that we were really talking about 2 sub-projects:

1. The relatively straightforward recording of capsule fruiting stages, maybe together with recording male organs when seen. This is intended to be primarily a field exercise, focussing on species that can readily be identified in the field – and we believe could be carried out in conjunction with regular field recording / square bashing.
2. More detailed monitoring of particular species, maybe even of specific populations, noting timing of various stages of the reproductive cycle and any other relevant observations. This will involve collecting material for investigation, for example dissecting perianths to observe developing sporophytes.

Rationale behind the project

There are several good reasons for carrying out a project of this type:

• General recording doesn’t appeal to everyone, for many reasons: lack of confidence and/or ID skills, an inbuilt aversion to square-bashing, doubts about the usefulness and meaning of the data generated. This project will provide a new purpose for going out looking at bryophytes. Importantly too, data will be contributing to global scientific knowledge in a perhaps more rewarding way.
• Having a focus on relatively few species that can be recognised in the field will be ideal for relative beginners. It will be a good way to encourage people to start to recording bryophytes in the field.
• Accurate information on sporophyte development might help to identify certain species
• Climate change is undoubtedly already having an impact on bryophytes, but we have very little baseline data on their phenology. Better late than never!
• It’s interesting and will teach even non-beginners to recognise the various reproductive structures that they’ve never thought to look for, and to be more curious about what they see under the microscope.

Aims of the project

• To record timings of sexual reproduction stages across a range of species and a range of locations within the UK and Ireland
• To record more detailed reproductive information for certain species, again in a range of locations / habitats
• To publish the results in Field Bryology and make data available to anyone who would like it.

Duration of the project

This has yet to be decided, but we should aim for at least 2 years recording effort initially.

Part 1: Field recording project

What to record

We have identified a list of target species, all of which should be identifiable in the field with a little practice. You can download a spreadsheet of these below. There is of course, nothing to stop you recording phenological information for all species you encounter, if it is easier to do that.

We propose recording the following ‘fruiting stages’ for mosses (see photos below):

1. Spears
2. Capsules swelling
3. Capsules fully expanded, but still green
4. Capsules changing colour
5. Capsules brown
6. Capsules without lids / dehisced
7. Dry empty capsules

For liverworts:

1. Green capsules visible in perianth or involucre
2. Black capsules and emergent sporophytes
3. Sporophytes with elongated seta/dehisced

For hornworts:

1. Undehisced capsules
2. Dehisced capsules

In addition:

1. Record presence of male organs when observed
2. For liverworts, record presence of perianths

The usual data should also be recorded i.e. recorder, date, location and/or grid reference (GR preferred). Altitude and habitat data are potentially of great interest when comparing data for the same species from different places, so please make an effort to note these too.

Note that multiple stages may be observed for any particular species at the same time / place, and all stages seen should be recorded.

How to record

Modified versions of the standard Excel spreadsheet are available to download below. These will enable the entry of multiple fruiting stages against each species, and will generate a separate spreadsheet with the detailed Phenology information. This sheet – called ‘To transfer (phenology)’ – should be sent to the Phenology project team (phenology@britishbryologicalsociety.org.uk). The standard ‘To transfer’ sheet will be unaffected and can be processed or sent to the Regional or National recorder as usual.

Alternatively you can use any method of your choosing, provided you record all the information above. If your standard method is not modifiable to capture separate fruiting stages, then please use any Comments or Note field and list stages separated by commas (for example ‘f1, f3, f4’).

Part 2: Species monitoring project

This part of the project will focus on monitoring particular populations of certain species, to record the timings of particular stages of the reproductive cycle.

Take a look at the Spotlight article by Jeff Duckett and Sylvia Pressel in the recent Field Bryology (available below) to see the kind of information that can be gleaned by this method, and the questions that might arise as a result.

Volunteers for this part of the project should be able to identify populations located reasonably close to home, which are fruiting or been observed fruiting in the past. These should then be monitored on a regular basis, with the results logged in a spreadsheet or similar, and submitted to the Phenology project team after at least one cycle has completed.

Monitoring of liverworts in particular will require microscopic examination to determine details that can’t be seen in the field.