Annals of the History and Philosophy of Biology

Plant systematics in Jena during the early 19 th century
P. E. Ventenat presented in this table the main principle of the “méthode naturelle” the
subordination of the plant features. A.-L. de Jussieu explained that each characteristic has
a relative value and accordingly the value of one variable feature could be equivalent to
the sum of the relative values of inconstant characters 71. In the following years Fr. S.
Voigt refined his point of view. The diagnosis of the natural family Campanulaceae in his
Lehrbuch der Botanik (1827) is an example of his procedure. It starts with the features of
the embryo, then those of the seed, the fruit, and the stamens etc., and finally the characteristics
of the stem. Placing the description of the embryo first shows how much Fr. S.
Voigt’s ideas had changed and matured since 1806 72. L. Cl. Richard had explained in his
Démonstrations botaniques (1808) 73 the constancy of the features of the embryo and especially
its position or the orientation of the radicle. L. Cl. Richard converted Fr. S. Voigt
to similar ideas, and the latter proposed in his Lehrbuch der Botanik (1827) the presence or
absence of the embryo as the most important character in classification 74, not simply the
number of cotyledons as used by A.-L. de Jussieu. The reception of the idea of the subordination
of the plant characteristics and the modifications of this concept by Fr. S.
Voigt illustrate his progress of thought, but this example does not give us an insight into
his own representation of the affinities of plants and his way of diffusing the natural
method to his students.
3.2. Fr. S. Voigt’s didactic treatment of plant affinities
In this part we explore chronologically the didactic treatment of plant systematic in his
teachings and textbooks. First, we wonder how Fr. S. Voigt taught the Linnean system.
We find a response to this question in his botanical dictionaries. In the first edition of his
Handwörterbuch der botanischen Kunstsprache (1803) the names of classes and families of the
Linnean sexual system were included. Furthermore, in his Übersicht der Naturgeschichte 75
(1819), a chapter is entitled: “Fehler und Inconsequenzen des Linneischen Systems, die aber nicht
verbessert, sondern nur studiert werden sollen”. Although he removed the Linnaean names in
the second edition 76 of his dictionary of 1824 on the pretext that they were well-known
by most botanists, he also stressed the preliminary and uncertain state of natural classification
and did not introduce the new taxon names of the “méthode naturelle”. These
first publications highlight the attitude of Fr. S. Voigt towards the Linnean system, which
71See Jussieu, A.-L. 1824. Op. cit. note 14: p. 352.
72 In his Genera Plantarum (1789), A.-L. de Jussieu began with the feature of the calyx, the stamen, the corolla
[…]: “Classis IX. Ordo IV. Campanulaceae: Calyx superus limbo diviso […]. Corolla summo calici inserta
[…]. Stamina ibidem inserta sub corollâ […].” Jussieu, A.-L. 1789. op. cit. note 3 : p. 163.
73 Richard, L. Cl. Démonstrations botaniques ou analyse du fruit considéré en général. Paris, Gabon, 1808: xii + 111 p.
74 Significance of the features of plants according to Fr. S. Voigt: “1. Anwesenheit oder Abwesenheit des Embryos.
2. Zahl der Cotyledonen. 3. Lage des Embryo im Saamen, und Anwesenheit oder Fehlen des Eiweißes. 4. Anheftungsart des
Saamens in der Früchthülle. 5. Bau der Frucht und ihres Offnens. 6. Verhältniss der Staubfäden zu den Stempeln. 7. zahl
des Geschlechtstheile. 8. Die Blumenkrone. 9. Der Blüthenstand. 10. Stellung der Blätter und Aeste Anwesenheit oder Abwesenheit
der Stipulae. 11. Der Gesammtbau, ob Bäume, Kräuter etc. 12. Die übrigen Qualitäten, ob es plantae lactescentes,
venenatae, aquaticae n. dgl. sind.” Voigt, Fr. S. 1827. Op. cit. note 2: pp. 209-210.
75Voigt, Fr. S. Übersicht der Naturgeschichte zum Gebrauch für höhere Schulen und zum Selbstunterricht. Jena, 1819.
76Voigt, Fr. S. Wörterbuch der botanischen Kusntsprache. Jena., A. Schmid, 1824.
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