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This site is entirely decicated to the Houseleeks, plants whose modest aspect however did not prevent that they were, a long ago, dedicated to the God of the Gods.


1. Aims

2. Object

3. Methodology

4. Imperfections and gaps

5. Examined works and articles

5.1. Notes about the literature devoted to this genus

1. Aims

The aim of this document is to present the genus Sempervivum L. under all its aspects, as well historical and cultural thab botanical or horticultural ones.

It constitutes an attempt of retrospective assessment and actualization of some knowledge (and gaps...) about the Houseleeks. This is however neither a revision of this one, nor a true identification guide of the species which make it up, but more simply a survey based on the compilation of existing data with personal observations and reflexions.

This document is produced, at lost moments, by a pure amateur in all the acceptance of this term:

To love is to know, to know is to understand... or at least to try !

Recent and more or less comprehensive documents dealing with the genus Sempervivum in its entirety are rather rare not to say inexisting (particularly in French). This document try to fill a gap while giving the opportunity to the amateur to save necessary time, difficulty (and... money) to get information, sometimes rare and always scattered here and there, this before a much needed complete revision is undertaken of this genus dubbed as "difficult" and now rather "out of fashion".

This notion of "difficult genus" is nothing more than the sign of the inadequacy of our way of thinking, of reasoning and of... classification to describe and understand the dynamic reality of Life processes. To understand what is behind the notion of "out of fashion" one should parallel it with the strong passion of the botanists of the end of the nineteenth century for this genus. The nomenclature of this genus has however retained the deep scars of those days...

2. Object

The content of this document amounts to the genus Sempervivum Linnaeus. However, the range of this term has noticeably changed with time. It is therefore necessary to make it clear what we shall be discusing here:

A. Sempervivum L. s.l. in the old sense

Aa. Aeonium Webb & Berthel. an other Macaronesian allied genera.
Ab. Sempervivum s.s. in the old sense

Ab. Sempervivum s.s. in the old sense
.........= Sempervivum s.l. in the modern sense

Ab1. Jovibarba in the modern sense (sensu Koch, Opiz)
Ab2. Sempervivum s.s. au in the modern sense

(s.s. = sensu stricto ; s.l. = sensu lato)

Aeonium tabulaeforme (Haworth) Webb & Berth.

This very beautiful Canarian species was at first described in 1819 as a Sempervivum (S. tabulaeforme Haworth) according to the extensive understanding of the genus at this time.
[in cultivation]

Throughout this document, the name Sempervivum must be understood as :

 Sempervivum sensu lato in the modern sense,
i.e. including the genus Sempervivum L. sensu stricto (genus Sempervivum subgenus Sempervivum or section Eu-Sempervivum Koch) and the genus Jovibarba Opiz (or subgenus or section Jovibarba DC. syn.: genus Diopogon Jord. & Fourr.) subsequently singled out from the first one.

It may also be understood as...

 Sempervivum sensu stricto in the old sense (i.e the Linneal sense),
i.e. excluding from the genus Sempervivum the Macaronesian genera Aeonium Webb & Berthel., Aichryson Webb & Berthel., Greenovia Webb, and Monanthes Haworth, which were first and long included in Sempervivum, at least pro parte. This latter group is obviously very close to Sempervivum s.s. but distribution areas, habitats, appearances, growth habits, as well as a seemingly internal homogeneity of this group together with with a break with Sempervivum s.s. are reasons to separate it from Sempervivum. Therefore, these neighbour genera will not be considered in this work, limited to the genus Sempervivum proper, though the reasons for this exclusion might well seem arbitrary.

However it was decided to maintain Jovibarba as a subordonate group to the genus Sempervivum or, at most, as a genus very close to it. This point of view is well-founded but remains debatable and the individualization of Jovibarba has serious arguments, as we will see.

3. Methodology

In 1924, under the pen of the illustrous Genevian botanist-gardener Henry Correvon (1854-1939), was published "Les Joubarbes". This work wanted to be the continuation of a previous work by John Gilbert Baker (Synopsis of Hardy Sempervivums, set of articles articles in Gardeners' Chronicle, 1879).

"Les Joubarbes" by Correvon constitutes the only rather wide monographic document (134 pp.) dealing with the genus Sempervivum in French language, and... remained the most recent still to date in this language !

[ to download this book ]

Henry Correvon (1854-1939)

The work of this famous author, as well as a monographic self-published booklet in 1991 by Howard Wills, an English and impassioned amateur-nurseryman, will be the the starting point of an interest which will increase quickly!

When one resides at the nose of Brittany, how to be interested and better know a genus whose closest representatives are several hundreds of kilometers away?... and the main part several thousands away! The problem is not simple. Some contacts with other people sharing the same interest were of course useful, as the opportunities provided by short holidays to observe these plants in their natural environment, at the price sometimes of some relational difficulties with my entourage for the choices of the itineraries...

Houseleeks are so varaible plants than it is difficult to study them without field observations AND parallel cultivation. So, it was necessary to care (the word is excessive) a small collection of natural forms, but prefering clearly to accumulate knowledge than flowerpots, this a little past.

Then, an eye on the field, the other on the cultivated plants, the nose in the books and the hands on the keyboard, here is the result: this document as a web site. Far still being completed, one may hope however it will bring as is some interesting information to the reader and that the interest for these plants will be communicative.


In some parts of this document, Houseleeks are sometimes the starting point to some digressions on subjects of a more general nature (even being close of out-subject...), and which could thus as easily apply to the study of other plants, when they do not escape from the strict topic of plants... To deal with a plant, or any other living organism, it is indeed often more rational and precise to take up certain general topics (about botany, biology, physiology, etc) and to illustrate them with the treated particular case, rather than to analyze this one from the start and separately then to make the synthesis of it only secondarily with the general laws. Moreover, this point of view makes the text less indigestible for someone firstly not particularly impassioned in the narrow topic of Houseleeks...

4. Imperfections and gaps

 Some parts of this document are still superficial, partial and incomplete, even concealing some errors and inconsistencies. They are still "under construction", one could say, because writing and setting of all that stuff take time and time is a rare product... However, a document partially unfinished but available and consultable is worth that a monumental work constantly postponed!

 Written by an addicted rather isolated in his corner, the text undoubtedly deviates sometimes (too often with the taste of certain purists) from the rigorous and austere (if not hollow and grand-sounding...) drafting and from the idea that it may be done for a document with pure and hard scientific claim. In the same way, the unquestioning gardening-guides-lovers will find there perhaps only trouble and useless fussy matter. It is indeed always difficult to follow without zigzaging the median way, which considers the reader neither as a half-witted one and good only for browse a picture-book, nor for an initiate for whom any clearness represents an insult to its knowledge, or worse, for a half-witted of which it is necessary "to put full the sight"... It is thus necessary to try to aim at the middle, all therefore lies in the capacity to aim accurately...

 The scarcity and the poor quality of the pictures is not a choice but a constraint. Many pictures of fair quality take a considerable place on the always limted space of the servers. As for the pen drawings, their execution requires a time and especially a talent that everyone does not have...

 To these formal imperfections is added an imperfection on the fond: the book learning and the observations resulting from the cultivation can supplement field knowledge usefully, but they will never be able to replace them. However, for reasons of geographical distance, free time, and... budget, those of the author are still to date null for all the Eastern part of the vast area of distribution of Sempervivum, and limit themselves to dream to that while browsing maps and atlases. Moreover, all the literature devoted to the genus unfortunately has not been able to be consulted, far from that, and the consulted one was not always fully understood... for reasons of languages.

5. Examined works and articles

See the Bibliography file to download: the references of used and studied publications for producing this document are quoted with an exclamation mark " ! ".

5.1. Notes about the literature devoted to this genus

If the documents relating to Houseleeks appear to be rather abundant (cf. bibliography), they are also in their great majority rather old and often extremely brief. They practically never adopt the form of a monograph, with some rare (and old) exceptions. Existing documentation thus is primarily based on the various floras and floristic catalogues of some zones of their distribution area, and on limited articles from periodicals, which contain often only simple quotations or floristic statements.

One can only note and deplore the great confusion which prevails over the literature, especially if a little old, about this genus and its nomenclature, in spite of a relatively limited number of species. Approximations, "random" identifications, fancy or slapdash publications of neo-taxa, nomina nuda, bad interpretations of former documents abound for this genus. In short, it is a muddle, a knot bag near of which the Gordian knot looks like a lace of shoe...

The data of some works often using, in whole or part, those of other works not yet consulted on this date, the apparent deficiencies of the bases of this document are thus minimized. However, one must, on this subject, deplore the double practice, which rules over many other fields, scientist ones or other, of " pumping " with excess, which is necessary and legitimate, but while often "forgetting" to quote ones sources, which is a fraud near of dishonesty to the reader-user, believing to consult original and checked data. Thus much of inaccuracies, doubtful assertions, even coarse stupid things become like Gospel because duplicated ad infinitum. Although I too used here only the first technique, I nevertheless tried to avoid misusing the second too much...

To thus allow oneself to criticize the errors, approximations, and ambiguities from works and points of view emanating sometimes from known and sometimes prestigious names of the microcosm of Botany, can seem a singular vanity on behalf of an "amateur". It is not at all, because what one easily admits with a benevolent indulgence on behalf of an amateur, one cannot tolerate it coming from "professionals" often wanting to be references in their matter. There resides all the comfort of the amateur status: this one is founded to criticize at the professional the same defects for which it is founded to request indulgence for itself



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