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| Hellebore Species Acknowledgements Much of the information regarding species hellebores in the wild comes from but a few sources, all of whom have extensive fieldwork experience. Most of the photos that are not my own are from Tim Murphy of Great Britain and Matthias Thomsen of Germany. I have also enjoyed extensive correspondence with each of them. Their kindness, generosity, and friendship are both welcome and inspirational. The articles by Will Mclewin and Brian Mathew on the genus have also been invaluable for my understanding of the complexity of the genus and species relationships. Intentions The information provided here is meant to appeal to as many people as possible, from those who are new to hellebores and have interest in learning more, to those with extensive experience who are interested in all available information on the genus. It does not claim to be definitive, and I will update/amend/edit the information continually in an attempt to make it as comprehensive, useful, and accurate as possible. As my own collection of true species grows and matures, I will be able to supplement the information here with notes on garden culture for each species in hopes of increasing the appreciation for species in the North American horticultural community. The variation in the species is often greater than that in the more popular hybrids, and many species exhibit qualities that would be welcome in almost any garden. Speciation, Provenance, and Gardens No species concept comfortably covers all life forms, and hellebores are particularly challenging because they do not always follow our definitions. Provenance is not only important for communicating effectively when referring to similar morphological populations of wild hellebores, it is also important for understanding growing conditions for particular plants that we use in our gardens. Viewing plants in the context of provenance often helps us determine the complex of factors that are not reflected in simplified USDA hardiness zones or the labels provided by nurseries. Not all species and hybrids are as vigorous in all garden conditions, so it is helpful to consider provenance when deciding which plants to include in the garden and where to place them. Consequently, it is important to correctly label plants in commerce. Often, plants sold under species epithets are in fact hybrids, which can be misleading. Complexity It's difficult to determine the eventual number of species (a good deal of fieldwork and discussion remains), but a fair estimate is somewhere in the range of 20 or so; the genus is rather small. Since plant populations overlap or approach one another and many hellebores are inter-specifically fertile, natural hybrids are likely in some areas, and intermediate forms occur in many populations. Many species are so polymorphic (and often closely resemble other species), that plants can be difficult to identify, even for specialists. For this reason, it is sometimes impossible to identify a plant based on its morphological characteristics alone. The complexity and confusion surrounding the genus, particularly within the group Helleborastrum, has generated much debate. There are often no simple answers, but pragmatic definitions are certainly possible. Generally, a hellebore species is defined after considering its morphological attributes; geographic distribution and degree of reproductive isolation from other plants with which it could otherwise interbreed freely; and DNA analysis. For practical purposes, we can speak of 'typical ranges' rather than types within a certain species, while admitting that at either end of those ranges characteristics may cease to appear typical and may in fact closely resemble those of other species. In the future, this site will include photos representing the ranges in foliage and flower of some of the more troublesome species for comparison. Recently, a significant amount of field and lab work has been conducted to help clarify some of the confusion surrounding hellebore species. Among species, it is the so-called acaulescent * plants that offer the greatest challenge, and perhaps particularly the Balkan species. Though the more genetically and geographically distinct species pose few problems, those that are not reproductively isolated and/or those that lack strong genetic distinction continue to preclude easy conclusions for taxonomists. *Acaulescent plants are those that typically do not produce above-ground stems. Caulescent plants are stemmed. See discussion at the main Hellebores page. Species The genus Helleborus includes: H. abruzzicus, H. argutifolius, H. atrorubens, H. bocconei, H. croaticus, H. cyclophyllus, H. dumetorum, H. foetidus, H. hercegovinus, H. istriacus, H. liguricus, H. lividus, H. multifidus, H. niger, H. occidentalis, H. odorus, H. orientalis, H. purpurescens, H. thibetanus, H. torquatus, H. vesicarius, and H. viridis.** ** A few things of note here: At the time of writing, H. abruzzicus and H. liguricus have not been formally accepted; however, a paper by Brian Mathew, Will McLewin, and Matthias Thomsen describing the plants and proposing the possibility of species status is scheduled to be published. I have also here referred to the following as species: H. bocconei, H. istriacus, and H. hercegovinus. In most recent literature, they are treated as subspecies of H. multifidus, e.g. here, 'H. multifidus' refers to 'H. multifidus subsp. multifidus'. And not least is the situation with plants that generally fall into the range of H. multifidus and H. torquatus. Many populations in the Balkans are very confusing and it could lead to a taxonomic shake-up. There are also very attractive plants further south that local botanist refer to as Helleborus serbicus. Following the divisions of Brian Mathew, hellebores are divided into six sections:
Hybrids Helleborus x hybridus: Refers to all hybrids between acaulescent species, between acaulescent species and H. x hybridus, and any of the offspring of such plants. The name also is used for acaulescent plants of unknown provenance in gardens and nurseries. This is somewhat problematic as it is helpful to list a parent when naming hybrids, but is unavoidable. Often H. orientalis was used as the type in the past, but it made no sense to use the 'Orientalis' epithet when talking about hybrids where H. orientalis may never have been involved. In cases where an acaulescent species of known provenance is used as a parent, it is still helpful to keep the species name in the description for one generation of seedlings. For example, seed collected from an open-pollinated H. torquatus plant in a garden full of hellebores could be called 'hybrid from torquatus'. If two plants of the same species are of known provenance and carefully hand-pollinated, the resulting seedlings may be considered 'true' species, but of course there is some some concern over what 'carefully' means here. More accurate, yet cumbersome, would be: 'from H. torquatus, hand-pollinated'. Caulescent hybrids:
These are the named hybrids, but many other hybrids occur and are possible. Some other crosses that are known to have been successful include: H. niger x H. vesicarius, H. niger x H. orientalis, H. niger x H. foetidus, H. niger x H. thibetanus. Helleborus niger typically serves as the seed parent in such crosses. |
