Today, with good reason, we would consider any description of lichens as incomplete, if only morphological, anatomical, and ecological characters, but not chemical ones were mentioned. Secondary metabolic products play an important part in lichen biology, and so they do in taxonomy. Lichen chemistry has quite a long history (which I will not bring into focus here), but it was not until the last decades, that chemical investigation in lichen taxonomy started to form an integral part of all serious taxonomic studies. Here we are about to honour an outstanding lichen-chemotaxonomist, who took a very active part in this development in Central Europe: Christian Leuckert.
Christian Leuckert was born in 1930 in Radeberg, a small city in Saxonia, near Dresden. He first studied pedagogics and became a teacher for elementary schools. After a few years of teaching, he decided to study Natural Sciences and so went back to university. He started at the University of Leipzig, but very soon changed to the Free University of Berlin. This, however, was far from what we usually call a “change”. It was an escape through the “iron curtain”, which in those days divided Germany.
In Berlin, Christian studied biology as well as chemistry and consequently became a chemotaxonomist – a chemotaxonomist sensu stricto, one who has a very profound knowledge and interest both in phytochemistry and in systematic botany. Early in 1965, he successfully took his Ph.D. thesis “On the lignan glycoside Arctiin, a chemotaxonomic character in the family Compositae” and then continued his research on lignans, flavonoids, and triterpenes and other secondary compounds of flowering plants.
Then, there came a sudden serious change in his career, and by the end of the year 1965 Berlin’s vascular plant taxonomy lost this promising young chemotaxonomist. The background to this was as follows: It happened that just at that time Josef Poelt accepted the chair in Systematic Botany at the Free University of Berlin. Josef was very anxious to establish a well-working chemical laboratory for lichenological research at his new institute. Looking for a talented, active scientist, able and willing to organise and lead such a lab, he eventually came upon Christian Leuckert. – Christian accepted and this was a lucky strike for lichenology; and it became the starting point for a most trustful and fruitful lifelong co-operation.
Christian soon proved to be not only an excellent scientist, but also a talented and skilful organiser, and last but not least a most unpretentious, kind, and helpful colleague, capable of mastering scientific problems as well as carrying out difficult negotiations with various institutions and persons. He soon became Josef’s “right hand” and most of the entire institution’s organisational work was placed on his shoulders. And there was an awful lot of it, at this time, when a new building for the Institute was discussed, planned, erected and finally moved into.
In 1970 Christian achieved his “Habilitation” (effectively his tenure) both in Systematic Botany and in Pharmacognosy. In the same year he was appointed a professor and in this position he continued to work up to his retirement in 1995. Although the lichenological family at Berlin became smaller, when Josef Poelt left the city in 1972 for Graz and I left for Munich in 1973, a group of lichenologists continued active lichenological research at the Institute of Plant Systematics and Plant Geography in Berlin: Christian and his team, often intermingled by lichenologists from many other universities, who came to learn new methods and to find help with their intricate chemotaxonomical problems.
Christian Leuckert’s service to lichenology is remarkable and is at least threefold:
(1) He most thoroughly taught lichen-chemotaxonomy to a very large group of students and scientists. The methods he used and taught differed markedly from what may be called “the usual ones”. As an experienced phytochemist Christian used a very large range of phytochemical methods. Various chromatographic methods, chromatogram spectral photometry, or mass spectrometry to mention only some examples. His students soon learned to be much more careful and to call it a “tentative analysis” rather than “identification” of a substance.
(2) Christian made considerable contributions to the chemotaxonomy of many lecanoralean genera: Acarospora, Cladonia, Dimelaena, Lecanora, Lecidea, Lepraria, Lobothallia, Parmelia, Pertusaria, Ophioparma, Rhizoplaca – to mention only some. He not only focused on the substances itself and on the chemotypes, but also on distribution patterns of chemotypes and on the localisation of the substances within the lichen. One of his special fields became the identification of xanthones by various methods, however with lichen mass spectrometry in the centre. Results can be found in his papers on Buellia, Lecanora, Lecidella and Pertusaria as well as in the doctoral theses of his students Bernd Hanko and Johannes Knoph. Most of his publications originated in teamwork and going through Christian’s many papers, one can count the names of some 40 scientists Christian co-operated with. Number one in this list is Josef Poelt with 14 joint papers. To be exact: With 14 joint published papers. There are many others, but Josef’s tragic death did not give him the chance to get all his parts ready for publication.
(3) Christian spent a very considerable part of his time in helping colleagues who came to him with problems in identifying lichen substances. The number of publications, in which his name is mentioned under “Acknowledgements”, is therefore legion.
To sum up, Christian Leuckert’s contributions to lichenology are very considerable. His impact on colleagues working in chemotaxonomy is difficult to overestimate.
It as a very great pleasure to me, that the International Association for Lichenology is now going to honour Christian Leuckert for his services to Lichenology with the Acharius Medal.
– Hannes Hertel