On the Trail of the Powdernoodle Polypore (Inonotus rickii) in CA
Inonotus rickii conidiome (asexual spores) on Schinus molle. USA: California, San Diego, Balboa Park. 30 Aug 2020.
Although I'd seen many photos from the eastern USA of these weird brown, dusty-stringy structures labeled Inonotus rickii, I had never seen them myself. Until this week. I always thought the species seemed bizarre… Inonotus as I was familiar with it was a genus of fairly standard-looking bracket polypores, usually with short-lived annual or biennial fruitbodies. But I. rickii looked to me more like a collapsed Stemonitis slime mold... how could this structure belong to a polypore?
As it turns out these powdernoodles are the asexual stage of the species – the whole mass of hyphae, setae, and asexual spores is apparently called a 'conidiome’ – they are so distinctly unpolypore-like that the asexual stage was once was named as a separate species – Ptychogaster cubensis.
I was surprised to see it in California – it is more commonly reported from the eastern half of the US, and I guess I had internalized that as some sort of actual distribution. I was just behind the curve: I. rickii was already known from SoCal from a handful of Pulk’s San Diego County observations, as well as the first California record (as Ptychogaster cubensis) more than a century ago!
The species has been recorded widely around the northern hemisphere – always on hardwoods as far as I can tell, but on a huge range of hosts within that constraint (Celtis, Hevea, Schinus, Alnus, Platanus). However, I was able to find one article in which researchers compared sequences from Florida and Europe with other Inonotus. Within samples labeled as ‘rickii’, these researchers recovered two strongly geographic structured clades (De Simone, 2011). This result is fairly unsurprising given the massive geographic range and variation in hosts, and especially given the taxonomically-deranging effect of distinctive morphology. Curiously, the species seems to be most common non non-native trees in urban settings no matter where it is recorded. Why would that be?
The fruiting I found was growing on a Peruvian Pepper Tree (Schinus molle) at the aptly-named Pepper Grove in Balboa Park, San Diego. These trees are native to South America and were supposedly introduced to CA by Spanish missionaries. At this location, S. molle grows intermixed with Brazilian Pepper Tree (Schinus terebinthifolium) – despite searching many of the surrounding trees, I only found I. rickii on one large old S. molle. I wonder if infections of I. rickii account for the commonly monstrously-galled appearance of many pepper trees in California?
Keep an eye out for this species and make a collection if you can! It would be good to compare our specimens against those from Florida and Europe – perhaps there are additional cryptic lineages involved here.
My observation is here: Inonotus rickii in Balboa Park