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Collariella robusta

Posted: Wed Dec 20, 2017 5:42 pm
by Chris Yeates
A collection of rabbit pellets made at the end of October has turned up some interesting fungi, as well as the common ones one often encounters. These inluded Delitschia winteri (seven previous Yorkshire records) and Coniochaeta leucoplaca (one previous Yorkshire record).

The most interesting one has now appeared after 7 weeks. Clearly a Chaetomium in the broad sense. This is a large and often critical genus, often isolated from soil, damp paper etc., and often from domestic settings - see the open access http://www.sciencedirect.com/science/ar ... 1616300197 for example. Over 400 species have been described in this and closely-allied genera; they are primarily cellulose degraders and accordingly are often more frequent on dung-straw mixtures than on pure dung - that said rabbit dung is often quite rich in only partially digested plant material. Doveri (2004) lists over 60 species which have been listed as strictly or occasionally associated with dung.

This particular fungus was keyed down as close to Collariella (Chaetomium) bostrychodes based on unbranched coiled hairs, a darkened ostiole, and pale grey broadly limoniform spores 6.1-6.7 x 4.8-5.4┬Ám, with a single germ pore. Indeed if only using Ellis & Ellis II that is what I would have named it. However after further delving into Doveri (2004) and von Arx et al.'s 1986 monograph my attention was drawn to a Chaetomium robustum (now transferred to Collariella), very close to C. bostrychodes, but diffentiated by the fact that while the whole peridium of the latter species is composed of textura angularis; that of Collariella robusta has the upper cells, as one approaches the ostiole, comprised of textura prismatica.
Tissue types.jpg
from Dictionary of the Fungi (2008)
This can be seen in the top right image in the accompanying plate, where the contrast between the cells at the bottom and the upper cells can be seen. I am very grateful to Dr Paul Cannon at Kew who has confirmed the identification:
Collariella robusta.jpg
Chris

Re: Collariella robusta

Posted: Fri Dec 22, 2017 10:55 am
by Pitufo
Very interesting and beautifully described. Thanks Chris.