Sheep milk and boletes

From the Gisborne Herald 20 August 2016:

A slow but certain interest in dairy sheep has started to build throughout New Zealand as some cornerstone corporate farmers cement the industry’s footing as a viable pastoral alternative to traditional land uses. … Globally the dairy sheep market is estimated to be worth US$8 billion at the farm gate …….

The Flock House homstead [photo]

The Flock House homstead [photo]

The summer of ’92

In the summer of 1992-1993 I was living and working at an AgResearch research farm, Flock House, in the Rangitikei. This was a period of massive restructuring in government science organisations and funding. It was the beginning of the modern period where incremental science became a dirty word and it was all about innovation and what would become ‘disruptive’ science.

Lambs on a modern litter system on a Landcorp farm near Taupo [photo Gerard Hutching]

Lambs on a modern litter system on a Landcorp farm near Taupo [photo Gerard Hutching]

One project the organisation was working on was the development of a flock of ewes for milking. To maintain lactation the lambs were removed from the ewes soon after birth. The lambs were kept in a big, covered, concrete floored yards to which my lab was attached. The floor of the yards had been boxed with slabs of untreated, rough cut Pinus radiata to create a bed that was about 20 cm deep. These beds were then filled with pine wood chips which formed a deep litter system to raise the lambs on. The wood chips absorbed the urine from the lambs.

A flash of yellow

After a few weeks of the lambs being penned on the litter I saw a bright yellow boletes growing on the wood chips. It completely confused me as at that time I only knew boletes to be mycorrhizal and not saprobic on wood. I could not identify it so filed it away.

Buchwaldoboletus sphaerocephalus from Flock House [picture Geoff Ridley]

Buchwaldoboletus sphaerocephalus from Flock House [picture Geoff Ridley]

I’ve seen you before!

That is until 2009 when I saw a picture of Buchwaldoboletus sphaerocephalus in the Field Mycologist (Weightman, 2009). Here was a picture of a bright yellow bolete with the caption: “This painting of Buchwaldoboletus sphaerocephalus is one of the earliest known of this rare species which grows on heaps of old sawdust“. And the text said of it:

Buchwaldoboletus sphaerocephalus (as Boletus sulfureus). An important early illustration of this rarity. It was sent from Brandon, Norfolk, Nov 3, 1876 by Plowright who probably also supplied the comment “from sawdust heaps only seen by Fries himself once”.

Buchwaldoboletus sphaerocephalus by Dr Henry Graves Bull, 1818-1885 [photo Royal Botanic Gardens, Kew]

Searching back through the literature I had to hand I found the comment: “Buchwaldoboletus (Boletaceae). This genus is world-wide although there are only a few constituent members; all grow generally on gymnospermic woods“. (Watling, 2002)

I have no doubt that I found my fungus. Given the bright yellow fruitbody it is surprising that we don’t see a lot more of this species in New Zealand. Particularly with the use of pine wood chip as garden much. A possibility is that it was the high nitrogen content in the litter from the lambs’ urine that triggered the fungus to fruit.

I also isolated managed to isolate it into culture and it has survived. It is slow growing and only forms a small mycelium and stains the media dark brown.

Buchwaldoboletus sphaerocephalus culture [photo Geoff Ridley]

Buchwaldoboletus sphaerocephalus culture [photo Geoff Ridley]

Further reading

Hutching G, 1996. New Zealand sheep milk gelato makes it to finals of global dairy awards.

Watling R, 2002. One bolete genus or …? Field Mycology 3: 84-88

Weightman J, 2009. Dr Bull’s paintings of fungi. Field Mycology 10: 113-121. [particularly p. 11]