Kew Fungarium (Week 5, Wednesday)

After a visit to the Herbarium, we couldn't miss the Fungarium.

What an amazing place! A fungarium is a collection of dried specimens, and Kew collection was recently complemented with a donation by CABI, to create one of the largest collection in the world. It contains 1.25 m specimens, including plenty of types - ca 45,000, and is continually growing, at the rate of ca 5,000 specimens a year.

Fungi are fascinating: not a plant, nor an animal, they make up a taxonomic kingdom of their own, their distinguishing characteristic being they contain chetin in their cell walls (plants contain cellulose instead) like that in the exoskeleton of insects. We know comparatively little about fungi, and reclassification is continually happening: our knowledgeable, and most entertaining, guide for the day, Begoña Aguirre-Hudson, mentioned three taxonomic reorganisations since she has been taking care of the collection...

... she features in a Kew video, about fungi and the Fungarium, available on YouTube, by the way.

We were shown an interesting selection of specimens: one collected by Darwin (which is more valuable from a historical point of view than for its scientific value: Darwin preserved his specimens in port wine for lack of anything else, apparently!); one was the renowned Chinese caterpillar fungus (a clever parasite of the caterpillar, indeed) and potato blight... plus some dried porcini, Amanita and giant puffballs...

The mycology department, where the Fungarium is located, also includes a lab where mushrooms are collected, cleaned, analysed, their genetic material extracted for any necessary DNA testing, and then dried to be added to the collection.

A special machine ensures the fungi are quickly dried at a low enough temperature to preserve their genetic material (40°C). Then they go into a freezer that can reach a temperature of -35°C so that all insects that might damage the specimen, and their eggs, are killed.

The specimens need to be packeted, glued to the archival paper and archived by hand.

They are also being digitised: records are available in the HerbIMI database, while a project is ongoing to get high resolution images of all the collections.

We were also given a leaflet on fungi: do you know why we really really need them?

• fungi recycle animal and vegetable waste so that the nutrients from them become yet available to the ecosystem;
• mycorrhizae: the relationships that many fungi form with particular plants, helping them extend the reach of their roots and absorb water and nutrients (phosphates in particular), but not only that, it appears they also help plants to communicate;
• many of our medicines derive from secondary compounds produced by fungi (including penicillin, a dried culture of which we had a look at in the Fungarium);
• yeasts, which help our bread rise, our beer brew, our wine ferment and any other fermentation... belong to the kingdom Fungi.

As a horticulturist, I am fascinated by mycorrhizae, such an amazing symbiotic relationship. One plant in US conifer forests, Sarcodes sanguinea, is completely unable to photosynthesize and gets all its nutrients from mycorrhizae! In the annotated picture from my RHS Level 3 exam (Adams, Bamford, Early Principles of Horticulture, Butterworth-Heinemann) there is some explanation of the two main types of mycorrhizae: endomycorrhyzae that penetrate root cells, and ectomycorrhyzae that extend into intercellular spaces. 

But fungi are interesting in themselves: take mycelium for example, the matter of which fungi are made, that looks like threads when under the soil in the formations called hypae, and then arrange to form fruiting bodies (the mushrooms, i.e. the familiar toadstools or brackets on trees) that produce spores through which fungi reproduce, rhizomorphs (the bootlace structures that honey fungus uses to absorbe nutrients) and sclerotia (hard masses of resting spores that remain in soil until the right conditions happen for vegetative development). Some of these structures are so different that different stages of a fungus' lifecycle had been identified as different fungi (one of the reasons why re-classification is taking place all the time)... and I won't even attempt to go into the systematics of fungi, the   way fungi are grouped, based of the features (mobile spores, spores in a sac or in a club etc) and modes of reproduction (sexual, asexual or both...). If  you want to know more about it, I found book Pest, Diseases & Disorders of Garden Plants by Buczacki & Harris quite comprehensive

Dips and bumps on the way (Week 5, Tuesday)

The David Nash at Kew exhibition has just closed, so sculptures and installations throughout the gardens are being dismantled, leaving behind rather large pits in the ground that need filling. So I am learning the art of filling holes, as part of our team days :)

The main issue with filling holes is to make sure they do not sink, leaving unsightly and potentially unsafe dips and bumps where people walk. Therefore, one has to make sure the filling is quite compact. In order to achieve that, a process was developed:

• Soil is taken in with tractors and spread in layers;
• The layers are treaded on, with a typical heels-in walk to ensure that the most weight is applied (if you see us going round in circles and walking funnily, that's why);
• The layers are raked with a landscape rake to ensure they are even;
• The pits are thus filled up to slightly above the surrounding ground level;
• The soil is levelled carefully;
• Grass seeds are sown and raked in gently;
• The area, in particular if large, is fenced off to allow grass to grow undisturbed.

Soil is taken to the pit

A layer of soil is treaded on

A layer ready for raking

Checking the filling is level

Grass sown , area fenced off

I did gardening at the weekend as well as during the week, and that meant I was so unbelievably tired, probably the most tired I've ever been, and therefore felt overwhelmed and started questioning my new career.

For someone that is used to work mainly in an office, for how much one can love it, physical work is demanding and takes some getting used to. I needed to pace myself throughout the task, as I felt that my muscles were not going to take much more, and because I was trying to conserve energy, it was even difficult to join in the team banter.

It is getting better now, my colleagues were very supportive, apparently everyone gets very tired if they do not get proper rest it's not only me being a relative newbie - but that is definitely something to take into consideration: you can get quite disheartened from sheer fatigue.