Tutsan Rust

[poschiavanus]

I’m developing a long list of questions about rust & smut taxonomy because of iNaturalist postings, but this one just came up:

For many years I’ve always assumed that rusts on Tutsan and some of it’s hybrids (e.g., (H. inodorum) are Melampsora hypericorum (e.g., based on Ellis & Ellis, bioimages, Collins Garden Pests) etc., but have been told that this is more likely Uredo androsaemi which doesn’t appear in the Basidiomycete checklist.

Kruse (2019: p 227) suggests that rust on “wild” Hypericum will be the former species and the latter on cultivated species (presumably Rose of Sharon, Tutsan & hybrids + more exotic spp.). Tutsan is not a native plant in Germany & doesn’t appear in the standard floras, so may only be casually bird-sown. See FloraWeb.

Yours,

A puzzled Posch.

[Chris Yeates]

Hi – just spotted this

In May I had an enquiry from my old Yorkshire mycologist chum Jerry Cooper – now discovering all sorts of exciting new stuff in New Zealand. Overestimating my knowledge of German he asked me this:

“Does this book (which you can download) say that Melamspora hypericorum is not the correct name for the rust on Hypericum androsaemum, and if so based on what evidence?

https://www.wsl.ch/de/publikationen/neomyceten-in-der-schweiz-stand-des-wissens-und-abschaetzung-des-schadpotentials-der-mit-pflanzen-assoziierten-gebietsfremden-pilze.html” class=”bbcode_url”>https://www.wsl.ch/de/publikationen/neomyceten-in-der-schweiz-stand-des-wissens-und-abschaetzung-des-schadpotentials-der-mit-pflanzen-assoziierten-gebietsfremden-pilze.html

It’s possible because de Candolle’s Uredo hypericorum is potentially lectotypified by the rust on H. perforatum and Wilson & Henderson note the possibility the H. androsaemum rust is different, but beyond that I can find no evidence to support this assertion which has come up online. If correct then the appropriate name would be Uredo androsaemi.

and, following my response, added [my added emphasis}:

The problem is that nothing is published or deposited in GenBank.

M. hypericorum would need to be epitypified (against a rust on H. androsaemeum from southern Europe – if genetically different). So currently those notes are unsubstantiated.

I tracked down de Candolle’s original publication of M. hypericorum (1869) and the potential alternative name Uredo androsaemi (1808) and they are more or less identical (nearly word for word) and both mention H. androsaemeum as the first host. So currently, at least, M. hypericorum is the correct name as far as I’m concerned.

Jerry”

HTH

Chris

[poschiavanus]

Thanks Chris, very helpful.

I see Julia Kruse is on Research Gate so may just message her directly. It looks as though the German-speaking (DACH) world may have changed the name, but not when or why.

She has a couple of blog posts, with photomicrographs, on the two species:

* M. hypericorum sensu auct. DACH

* M. hypericorum sensu auct. brit.

Jerry

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