When Mushrooms Grow Hair: Spinellus and Syzygites megalocarpus

Spinellus fusiger parasitizes Mycena species, like this M. haematopus.

Spinellus fusiger

Though it's hot as stink outside right now, and dry, to boot, most of this summer has been unseasonably cool and moist—perfect growing conditions for all kinds of interesting fungal fruitings, including one I've wanted to see for years, Spinellus fusiger. The weather has, in fact, been so accommodating that I've found this spectacular bread-mould-related growth four separate times. It's hard to care about how crummy the weather is for swimming when hair-raising characters like this keep appearing in the woods.

The long, erect sporangiophores of Spinellus fusiger make the
mushrooms they attack look as if they've been electrocuted.

Spinellus species are parasites that attack your basic mushroom-looking mushroom, and are, in my humble opinion, wonderfully photogenic. The most common in these parts, S. fusiger, prefers Mycena species as its victims, often M. haematopus, which, even when its cap is sprouting a crazy new fungal hair-do, can still be identified by snapping its stem to look for its characteristic "blood."

Spinellus species grow long erect "sporangiophores" tipped by 

spherical spore-producing bodies that darken as spores mature.

Mucorales

Spinellus species belong to the order Mucorales, or "pin molds," in the phylum Zygomycota. The hyphae of these fungi, unlike those of ascomycetes or basidiomycetes, are rarely septate, which means they have no barriers to slow the movement of cytoplasm, allowing them to grow extremely quickly. If you've ever had a loaf of bread that's been colonized by the less spectacular, but much more common mucorale, Rhizopus stolonifer, or black bread mould, you will understand how quickly these fungi can grow.  

Hundreds of asexual Spinellus spores are produced by each sporangium. 

All mucorales produce spores in tiny globose sporangia held at the tips of sometimes very long specialized hyphae called sporangiophores. Though mucorales are capable of reproducing both sexually and asexually, the vast majority of spores are anamorphic, or asexual. 

The stalks of Spinellus, and all other mucorales, 
have a swelling at the tip called a columella.

The balloon-like columellae persist after spore dispersal.

Syzygites megalocarpes

Another woodland mycoparasitic mucorale, is Syzygites megalocarpus. The only species in its genus, S. megalocarpus is nowhere near as choosy about its victims as S. fusiger and has, so far, been found on 65 different genera. It's easily recognized by its multi-branched sporangiophores that make the fungi they parasitize look as if they've not only grown hair, but hair that desperately needs frizz-control. When they first start growing, these sporangiophores are deep yellow due to the carotenoid pigments they produce, but become paler as they stretch out, and eventually turn a more traditional mould colour—bluish gray. 

This Syzygites has made an Amanita flavoconia almost unrecognizable.

This Syzygites megalocarpus appeared overnight on a
Boletus subvelutipes left out on my dining-room table.

An ethereal veil of Syzygites megalocarpus hangs 
from the cap of a small Pluteus species.

Though I've found S. megalocarpus a number of times, they've always either been past their prime or I've been without camera, so I had no usable in situ photographs for this post. Ever the optimist, though, I went out in search of one a few days ago, before this heat wave hit, and—lucky me!—I found a beauty in full glory that had infested a Pluteus growing picturesquely on a log. 

The sporangiophores of Syzygites megalocarpus are 
dichotomously branched up to six times. 

Asexual spores of Syzygites megalocarpus are 
produced on the tips of branched sporangiophores.

So what does a cold summer have to do with finding Spinellus fusiger for the first time? Well, it turns out that Spinellus species, as well as S. megalocarpus, are temperature sensitive, with a distinct preference for cooler weather. Spinellus are the pickiest, requiring temperatures to be lower than 22ºC to grow. I don't know about where you live, but summers here in Ontario have become so consistently hot over the past twenty years that a high of 22ºC has come to be considered "cold." Is it coincidence that, though I'd never come across it before, I stumbled upon Spinellus four separate times this season? I doubt it. And because I doubt it, I'm adding the previous dearth of Spinellus to my growing list of local anecdotal evidence that fungi fructifications are being affected by climate change.   



References:

Syzygites megalocarpus on Mycoquebec
Spinellus fusiger on Mycoquebec
Zygomycota
Mucorales
McLaughlin, D. J., E. G. McLaughlin, and P. A. Lemke. 2001. The Mycota VIIA: Systematics and Evolution. Springer-Verlag, New York.  
Hoffmann, K., Pawlowska, J., Walther, G., Wrzosek, M., de Hoog, G. S., Benny, G. L., ... & Voigt, K. (2013) The family structure of the Mucorales: a synoptic revision based on comprehensive multigene-genealogies. Persoonia 30: 57-76.


Fun: 
Time-lapse video of Syzygites growing