Species hellebores

Introduction

I did say I wasn’t going to mention species hellebores, but looking at the variation in size, leaf shape and habit of the garden hybrids, I decided I wanted to see which species may have had influence on them. I had a few species already, but I have set out to find as many as I can (and if you can help with that I would be eternally grateful, please contact me through Facebook or Insta!).

Unfortunately I stumbled across some kind of prickly Victorian gentleman’s club of species hellebore specialists (very different to the hybrid hellebore fans who are more than happy to share information and more), and came to a full stop. But what I did find out is that it seems no one has really agreed on the classification of some of the species, and that it is definitely tricky.

Plants Of The World Online, (POWO), of which Kew is part, lists 15 different species. Wikipedia lists 20 species, naming them slightly differently. I do not know who created the Wikipedia entry, it’s a shame you can’t see who performed the edits. However the entries seem to match with a now defunct website hellebores.org, which can be viewed on the Wayback Machine here. Other hellebore specialists list different numbers of species, even species names unique to their own studies. Just to clarify that the issue lays within the group Helleborastrum. Species in other groups can be more easily defined.

Plants within Helleborastrum species themselves are very variable. Whether there has been much crossing in the wild before humans ever decided to try giving them names, or at the other end of the evolutionary scale whether the species have not been separated for long enough to become very different, is unknown. But, as a plant biologist by trade, I would be inclined believe that each ‘species’ has not been clearly geographically separated from each other for long enough because to define something as a different species, it simply can’t be as variable and as similar to the ones nearby (geographically speaking) as people seem to have found them to be in the wild. Although the technical definition of a species is where members of it look similar and can produce fertile offspring, which is rather vague.

Experts say that to classify a hellebore plant you must know where it came from – i.e. features alone are so variable they are not enough to distinguish between the species clearly enough. Is this enough for them to be classed as different species?

Maybe I would err more on the side of the 20 species mentioned on Wikipedia rather than the 15 on POWO, but I would not rule out some of these being crosses between other species where their ranges overlap. Or maybe they are simply a genetic sliding scale, like the breeds of gulls whose territories circle the northern hemisphere. Where each species can produce fertile offspring with the one next to it but not with the one on the opposite side of the world. Maybe H. thibetanus is that species on the opposite side as it has been longer separated from others. It is human nature to identify, assign and name things so perhaps we are creating species where there is not enough difference or separation. Although it certainly helps to be able to predict what a plant (sort of) looks like if you are given its species name.

*disclaimer – this is just an observation having read available texts, I have not managed to see many examples of species plants myself and I have not seen them in the wild. I own only one or two examples of just a few of the species.

The species…what we might know

I will start with the easy part – there are three groups (not official classifications, just easiest to show the differences). Those with stems (H. foetidus, H. argutifolius and H. lividus), and H. niger, plus the others. 

The genus is split into six sections. Some species have their own section – H. foetidus, H. niger, H. thibentanus, H. vesicarius are the only members of their sections. H. lividus and H. argutifolius belong to the fifth section. Then there is the last section, Helleborastrum, and this is where the issues lie.

This is just section Helleborastrum:

Interesting that whereas POWO claims H. croaticus is just a synonym for H. torquatus, World Flora Online declares it a recognised species. Also interesting that my H. croaticus plant bears no resemblance to the description of H. torquatus given by one of the UK’s hellebore specialists, Graham Rice (who also recognises H. croaticus as a separate species). Nor to the H. torquatus plant I owned about 15 years ago. 

Or that POWO’s description and image of H. multifidus subsp. bocconei is very different to the other H. multifidus subspecies and comes from a different area of Europe to them so why should it be the same species? And if the plants of H. liguricus I have in the garden are nothing like H. abruzzicus it’s very hard to see why they were both subspecies of H. viridis, which is quite different again. And that is why I am leaning to the larger number of species being more accurate. Please note I do not own very many species plants, and only one of each, so this is just speculation. 

Another point of (mild) interest is that on both Wikipedia and POWO, occidentalis is a subspecies of viridis, yet on the defunct website hellebores.org it is listed as a separate species H. occidentalis. I have plants from two different sources with the two different names, and they look very similar. The problem is that I do not have a H. viridis to compare them to!

The three species below are all listed as subspecies of H. viridis on POWO. Additionally, H. occidentalis is noted to be found in Britain, France and the edges of neighbouring countries. H. liguricus is found in northern Italy and H. abrizzicus in central Italy. I’m not sure I would have placed these in the same species if they are not close to each other geographically.

A paper published in 2010 by Julia Meiners, Thomas Debener, Guenther Schweizer and Traud Winkelmann titled Analysis of the taxonomic subdivision within the genus Helleborus by nuclear DNA content and genome-wide DNA markers lists 22 species in total, 16 in group Helleborastrum but no subspecies:

H. abruzzicus, H. atrorubens, H. bocconei , H. croaticus, H. cyclophyllus, H. dumetorum, H. hercegovinus, H. orientalis, H. istriacus, H. liguricus, H. multifidus, H. occidentalis, H. odorus, H. purpurascens, H. torquatus, and H. viridis.

A book, written by long-time hellebore researcher and specialist Will McLewin, is available – Helleborus and the Helleborastrum problem – where he presents his findings. He lists 21 species in group Helleborastrum alone, including some not mentioned elsewhere – H. malyi, H. bosniacus, H. gočensis, H. guttatus, and H. abchasicus.

Species at the Hellebore Garden

The species I have that are fairly well known and easy to obtain are H. argutifolius, H. niger in the form of ‘Harvington Double Petticoat’, H. foetidus and H. lividus ‘Purple Marble’ and ‘Lilac Marble’. 

Other named species I have managed to find include H. thibetanus, still a young plant and has not flowered yet. H. croaticus in a lovely floriferous form with starry deep red purple flowers flushed with green. Also H. abruzzicus (shown in main pic), H. liguricus, H. cyclophyllus, H. odorus (a beautifully scented plant) and H. occidentalis. 

I also have H. purpurascens, H. multifidus subsp. multifidus and a plant labelled H. viridis subsp. occidentalis from Broadleigh Bulbs, although I do not know where these originally came from. However I also was sent a plant labelled H. caucasicus which is a previously used name for H. orientalis subsp. orientalis so I can assume the plants have been at Broadleigh for many years if it was obtained by them under that name. 

More recently I have obtained H. torquatus, H. cyclophyllus, H. orientalis subsp. abchasicus, H. dumetorum and H. abruzzicus so am looking forward to comparing the latter to the plants I have.

This means I’m still searching for other species like H. atrorubens, istriacus and guttatus. I’m also keen to find plants of all the species to be able to compare them to the ones I already have, as I’ve no idea if they are really are typical of the species. 

H. vesicarius maybe a step too far, as it is quite different from the other species and harder to provide the right conditions for it. I have enough trouble with H. lividus and H. x sternii which have to live under cover in rather damp Cornwall!