Octospora 'humosa group'

Holt, ACT

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Identification history

	Octospora 'humosa group'	1 Sep 2020	Heino1
	Octospora sp.	18 Aug 2020	Heino1

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User's notes

Herbarium collection HL6429 at CANB

2 comments

Heino1 wrote:

18 Aug 2020

The inset at the lower left of the composite image shows a single spore and the circle is an oil drop within the spore. To the right you see four spores lined up within a tube-like ascus. A little to to the right of the rightmost spore you see the rounded apex of the ascus. You also see several of the narrow paraphyses (which act as a filler between neighbouring asci) and within the paraphyses there is the orange pigment that gives the fruitbody its colour. In this species the spores are smooth. For contrast compare the macroscopically similar Lamprospora australis (https://canberra.naturemapr.org/Sightings/4300532), where the spores have a mesh-like ornamentation.

Heino1 wrote:

1 Sep 2020

I thank Jan Eckstein & Lucas Janosik for comments about the identity of this collection. I have added a third image in which the subject is shown via dark field illumination. A small sample of tissue has been placed in a drop of water on a slide and gently squashed to spread it a little. In standard microscopy a light beam comes up from below the slide, passes directly through the sample and generates an image, in eye or camera. Here, the central part of that light beam is blocked before it can reach the sample. Light now comes into the sample from all sides at an oblique angle and the image is formed by light that has been scattered by the sample. Where there is nothing to scatter the light, you see black. A little below the centre of this image you see the same 4-spored ascus that appeared in the lower part of the second image. The oil droplet in each spore shows well, as do the bright pigment 'granules' in the narrow paraphyses. The two fuzzy circles in the upper left quarter of this image are oil drops in out of focus spores in the background.

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