Auck­land

The men­tion of fungi of­ten in­vokes vi­sions of rusts, blights and rots.

NZ Gardener - - Contents -

Dr Trevor Crosby looks at the fungi you might find in your gar­den

To many gar­den­ers, these mean ru­ina­tion of prized plants and crops, as well as the spoil­ing of hard-earned pro­duce.

However, there are many ben­e­fi­cial fungi, such as those form­ing my­c­or­rhizal as­so­ci­a­tions, that lead to the suc­cess of land plants. Then there are all those fungi that live on dead plant material (sapro­phytes) and break it down so it becomes avail­able to other life forms.

In re­turn, many or­gan­isms are de­pen­dent upon fungi as food.

Much of the time, the fun­gal net­works of fine hy­phae are in­vis­i­ble to us. It is only when their re­pro­duc­tive stages ap­pear – in the form of mush­rooms – that their di­ver­sity of shape, form and colour becomes ap­par­ent to the gar­dener’s naked eye.

In New Zealand, there are some 8400 species of fungi recog­nised, but it is es­ti­mated that the true number is more likely to be around 23,000 species.

The mul­ti­lay­ered food for­est at the Sanc­tu­ary Mahi Whenua, at the Mt Al­bert cam­pus of Unitec In­sti­tute of Tech­nol­ogy, was started in 1999 and is now part of a sus­tain­able ecosys­tem. Orig­i­nal nurs­ery trees have been felled and, to­gether with pruned branches from re­tained trees, left in the food for­est to de­com­pose nat­u­rally. Now a range of de­com­pos­ing fungi is ap­pear­ing.

The south­ern cinnabar poly­pore fun­gus, Py­c­no­porus coc­cineus, is a bright orange-red bracket fun­gus.

It can mea­sure 10cm x 8cm in size and over time, the in­ten­sity of the colour fades.

Found in both Australia and New Zealand, it is a white-rot de­com­poser of wood, and pro­duces pow­er­ful lig­nolytic en­zymes (lac­cases) to break down lignin and tough polysac­cha­rides in the wood in a way that few other or­gan­isms can do as well. This makes it an important species in the break­down of wood as it makes the byprod­ucts of the process avail­able for use by other or­gan­isms.

The lac­case en­zymes have also shown po­ten­tial to be used in biotech­nol­ogy pro­cesses.

The turkey tail fun­gus Tram­etes

ver­si­color has strik­ing con­cen­tric zones of brown and tan on the up­per sur­face.

Its un­der­sur­face is white. Over time, green al­gae can grow over the up­per sur­face, mak­ing this fun­gus less ob­vi­ous. This world­wide species is 8cm × 5cm and the leath­ery-tex­tured flesh is about 1-3mm thick.

Turkey tail is recog­nised as a medic­i­nal mush­room in Chi­nese medicine (yun zhi) and in Ja­pan.

In the food for­est, turkey tail fungi have been found mainly on stumps and large branches of the nurs­ery po­plar trees that were felled about two years ago.

The na­tive ed­i­ble wood ear fun­gus,

Auric­u­laria cornea, is a com­mon wood-de­cay­ing fun­gus.

It mea­sures 15cm × 8cm in size and can be found at all times of the year.

Its flavour is gen­er­ally re­garded as in­sipid and is noted more for its texture, espe­cially in Chi­nese cui­sine: it has been de­scribed as a bit like tender ba­con rind. Maori knew this fun­gus as hakeka, and it is said that they only ate it when bet­ter food was in short sup­ply.

In the late 19th cen­tury, large quan­ti­ties were col­lected and dried for ex­port to China, espe­cially from Taranaki where it be­came known as “Taranaki wool”.

And fi­nally, if you’re going, “Wow amaz­ing? Is it real? A space­ship! What flower is that?”

Worry not. You are only feel­ing the sense of un­re­al­ity that is com­mon in first en­coun­ters with the earth­star fun­gus. This 5-7cm wide ined­i­ble mush­room, Geas­trum tenuipes, is na­tive to New Zealand though it is un­com­mon. It lives in and breaks down leaf lit­ter.

This fun­gus looks like a puff­ball fun­gus when it first breaks the sur­face. Then the outer layer of tis­sue splits open to give pointed rays of a star that bend and el­e­vate the in­ner 2cm di­am­e­ter spore case from its im­me­di­ate sur­round­ings.

Drops of water fall­ing onto the flex­i­ble, thin-skinned spore case gen­er­ate a suf­fi­cient pres­sure change within the spore case to force a puff of spores through the small open­ing on top.

The soft tis­sue of the pointed rays soon dis­ap­pears, pre­sum­ably through be­ing eaten by a range of in­ver­te­brates.

So next time you be­moan the ef­fects of un­wanted fungi on your plants or pro­duce, re­mem­ber that these fun­gal species are qui­etly do­ing what they do best – en­sur­ing locked-up nu­tri­ents in dead plant material are re­leased for use by other or­gan­isms in your gar­den.

South­ern cinnabar poly­pore fun­gus, Py­c­no­porus coc­cineus.

Earth­star fun­gus, Geas­trum tenuipes.

Wood ear fun­gus, Auric­u­laria cornea.

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