Rubus umbrosus (Weihe & Nees) Arrh.

Rubus umbrosus (Weihe & Nees) Arrh. – the correct name of Rubus pyramidalis Auct. non Kalt.

When I was a young batologist and read the section on Rubus in the appendix of Kaltenbach’s Flora des Achener Beckens (Kaltenbach 1845) I got the impression that the description of his R. angustifolius fits better to the plant that we presently call R. pyramidalis Kalt. (for convenience I use for this the label ‘our R. pyramidalis’ in this article) than the one about his R. pyramidalis. The authority of the whole batological tradition, however, and the remark by Focke (1877) that he saw a specimen authenticum persuaded me to keep to the traditional use, and by lack of any specimen authenticum (the one that Focke saw was probably burnt in B during World War II) I chose a neotype for R. pyramidalis in conformity to common use (Van de Beek 1974).

My doubts increased when I found a specimen of R. angustifolius from Kaltenbach’s own collection in W which was indeed ‘our R. pyramidalis’. After Matzke-Hajek received a specimen of R. angustifolius from DR which was also the same taxon (Matzke-Hajek 1998), there was no doubt that R. angustifolius Kalt. is the species that we labeled as R. pyramidalis.

It is hard to imagine that Kaltenbach who was not a splitter like his successor in batology in Aachen, A. Foerster (1878) would describe one and the same species in one and the same publication twice with different names, and one of those even with a variety, while all varieties by Kaltenbach of which we know the identity now are presently considered as separate species. A careful comparison of the descriptions of R. angustifolius and R. pyramidalis in the publication of Kaltenbach can result in but one conclusion: his R. pyramidalis is not ‘our R. pyramidalis’.

I give only a few examples:

-         - One of the most conspicuous characteristics of ‘our R. pyramidalis’ are the very soft pectinate hairs at the downside of the leaves. In the description of R. angustifolius Kaltenbach writes: ‘unten grün, sehr weich anzufühlen, auf den Rippen sammftig behaart’ (downsides green very soft to the touch, velvety hairy on the veins). This fits exactly to ‘our R. pyramidalis’. In the description of R. pyramidalis we read: ‘unterseits graugrün, auf den Rippen und Adern striegelig behaart’ (downsides greyish green, with pectinately arranged hairs on the nerves and veins’). As such we could interpret this that it fits to ‘our pyramidalis’ but if we compare it to the description of R. angustifolius the conclusion must be different: more grey and with only hairs on the nerves. This can also be a hairiness like R. rudis has. Anyway, it is not velvety soft as with R. angustifolius.

-         - Kaltenbach writes ‘Blüthenstengel (err. typ. Blattstengel) fast kahl’ (flowering branch almost glabrous). This cannot be ‘our R. pyramidalis’.

-         - According to Kaltenbach the stipules are lanceolate. I only once saw this with ‘our R. pyramidalis’ with a specimen that was also strange in other characteristics. Normally the stipules are linear as Kaltenbach mentions with R. angustifolius.

There can be just one conclusion: ‘our R. pyramidalis’ is R. angustifolius Kalt. and his R. pyramidalis is something else. I will not speculate about its identity. Time and again it has turned out that an identification based on a description only was wrong. One must see the plant.

What, then, about Focke’s remark that he saw a specimen authenticum? Also Focke made misidentifications, as we have seen in case of R. adspersus/platyacanthus – and other identifications of his, as well. All of us make that kind of mistakes and a close reading of the protologues shows that this is one by Focke.

Because Kaltenbach 1845 is a very rare book I attach photos of my old photostats to this article.

Before jumping to the conclusion that R. angustifolius Kalt. must be the correct name of ‘our R. pyramidalis’ now, we must take into account something else. Weihe & Nees (1824) described ‘R. pyramidalis’ as R. vulgaris var. umbrosus (lectotype in BREM; other authentic specimens in KIEL and HAL – Mr. Uwe Braun was so kind sending me a scan of the latter). Arrhenius (1839) brought this variety to the level of a subspecies and somewhat later he speaks unconditionally on the species level about R. umbrosus Weihe (1840 - a full reference was not required by that time: ICN, art 41.3). Because this publication is earlier than Kaltenbach’s (even if we take into account that his ‘Nachtrag’ of the Flora was published separately a year earlier than the Flora, as Weber discovered) the correct name of the taxon must be R. umbrosus (Weihe & Nees) Arrh. This is not just a matter of nomenclature, finding an older synonym of a taxon, but has to do with the right understanding of R. pyramidalis which is not a synonym of R. umbrosus.

The synonymy is as follows, then: Rubus umbrosus (Weihe & Nees) Arrh. = R. angustifolius Kalt. = R. umbraticus P.J.Müll. = R. pyramidalis Auct. non Kalt.

The synonymy of R. villosus Lasch (1833) to R. umbrosus, which is sometimes mentioned is not right. Though the specimen of Lasch is R. umbrosus, the editor of his publication, in the corrections which are published at the same date, identifies R. villosus explicitly with R. radula Weihe (Lasch 1833: 315), so that R. villosus Lasch is a later synonym of R. radula.

Literature:

Arrhenius, J.P. 1839. Monographia Ruborum Sueciae. Wahlström & Låstrom, Uppsala.

-        -  1840. Om de karakterer, som kunna tagas af Semina, vid bestämmandat af Rubus-arterne. Bot. Not. 6: 92–95.

Focke, W.O. 1877. Synopsis ruborum Germaniae: Die deutschen Brombeerarten ausführlich beschrieben und erläutert, p. 46. Müller, Bremen.

Foerster, A. 1878. Flora Excursiora des Regierungsbezirkes Aachen sowie der angrenzenden Gebiete der belgischen und holländischen Provinz Limburg. Rudolph Barth, Aachen.

Kaltenbach, J.H. 1845. Flora des Aachener Beckens. Boisserée, Aken.

Lasch, W. 1833. Die Rubusformen, welche und wie sie um Driesen wildwachsen. Linnaea 8: 293-315.

Matzke-Hajek, G. 1998. Die Identität von Rubus angustifolius Kalt. und Rubus obscurus Kalt. Decheniana 151: 89–93.

Van de Beek, A. 1974. Die Brombeeren des geldrischen Distriktes innerhalb der Flora der Niederlande. Meded. Bot. Mus. Herb. Rijks Univ. Utrecht 415: 1–112.