Foray NL Hydnum Project

A THREE KEY approach to IDENTIFYING the HYDNUMS of NL

KEY 1, rough tentative key

Use the species descriptions from two recent large studies by Niskanen et al. in 2018 (https://www.tandfonline.com/doi/abs/10.1080/00275514.2018.1477004) and Swenie et al. later the same year (https://mycokeys.pensoft.net/article/27369/) to make a key of species we are likely to encounter here.

All eastern North American species are unlikely to be native here. The following four groups are arranged in order of likelihood to be native in NL (my guess).

Group 1 FOR SURE

(because Kare Liimatainen sequenced some of my collections and identified)

• H. subolympicum, large with decurrent teeth, under birch
• H. washingtonianum, large with decurrent teeth, under conifers [named H. neorepandum by Niskanen et al., but since shown by Swenie et al. to be the same as H. washingtonianum, an earlier name]
• H. canadense, small, reddish, distinct cap and stem, under conifers
• H. quebecense, small, very reddish, distinct cap and stem, often in Sphagnum, likely Larix, partner
• H. submulsicolor, small, reddish, distinct cap and stem, under conifers
• H. umbilicatum, small, reddish, distinct cap and stem, under conifers

Group 2 LIKELY

(because some finds seem to fit)

• H. aerostatisporum whitish, small but robust, stains reddish, under conifers [named by Niskanen et al. as H. subrufescens, but since shown by Swenie et al. to be the same as (or VERY close) H. aerostatisporum, described a year earlier, and thus becoming the correct name.
• H. alboaurantiacum
• H. mulsicolor

Group 3 POSSIBLE

(not sure I have seen these, but some pictures seem to fit)

• H. albomagnum
• H. subtilior

Group 4 UNLIKELY

• H. albidum**
• H. ferruginescens
• H. geminum
• H. rufescens
• H. subconnatum
• H. vagabundum

Instructions: Start with the 11 spp of Groups 1–3. See where you get and if there are some that do not fit, then look to Group 4. Two major recent studies make unknown species unlikely (but not impossible).

KEY 2, better tentative key

Test KEY 1 with the iNaturalist project to see how well it identifies the finds, which species to include, which to drop, and which finds need more help. Refine characters and descriptions from the finds. This will produce a more accurate and circumscribed Key 2. Rachel has agreed to help with this part.

KEY 3, definitive key in 3 steps

A.

The simplest way to learn what species are native to NL (rather than my guesses) is to sequence available FNL hydnums, collected over 16 years from many different habitats all over the province. FNL has over 80 such collections, about 40 with photos. A wide representative selection of these is highly likely to contain all of our native species. Rachel has agreed to try to sequence such a sampling. The results, to which any other sequence-identified species are added, should tell us which species to include and which to drop for a key including all our native species, unencumbered by others.

B.

Use our database and photos to try to identify micro- and macroscopic characters that help differentiate these species from each other. This retrospective review should refine the key and make it very accurate.

C.

To further refine the key, test it prospectively by the iNaturalist project. We may need to sequence the odd collection that does not fit, but after testing, it should serve us for decades in the correct identification of our hydnums.

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'* The results from Kare Liimatainen’s sequencing, of Andrus Voitk’s Hydnum collections, is posted under “News” on the Foray NL Hydnum Project iNaturalist site.

** Hydnum albidum prompted my interest in our hydnums—something I hope this project will finish. I was pleased to note that Rachel Swenie, in her excellent presentation, thought H. albidum should be native to NL. This was exactly what I thought, because a) the species was described by Peck, b) most species described by Peck have been found here, and c) Peck’s collecting area lies in the same isotherm as most of Newfoundland. In the early years of our forays, H. albidum was often applied to white hydnums, but these were invariably large, usually with decurrent teeth, and H. albidum is a very small species with a definite break between cap and stem, so the name seemed misapplied. After some discussion, we decided relatively early to apply H. albomagnum to all our large white hydnums, until the genus was studied. Because neither the forays nor I have found such small white hydnums in almost 20 years, I now suspect that this species is not native here, and may have been at its northern limit in NY. It is a nice species, so I should be happy to be wrong. less ↑