6 — 



Preamble. 



In agreeinent with the Supplement to the „Lois de la noinenclature", 

 proposed by a group of Belgian and Swiss botanists*), a liet will be given 

 of tbose generic names of the Siphonogamae, which, for the sake of con- 

 venience, will be retained (nomina cori servanda), although, if the principle 

 of priority were strictly observed, they would bave to be replaced by older 

 Synonyms. The older Synonyms will be added to each generic name 

 (nomina rejicienda). Such a list, in an enlarged and more revised form 

 than that found in the Ber. Deutsch, bot. Ges. X. (1892) 332, is planned 

 by the above mentioned group of Belgian and Swiss botanists as an 

 Appendix to the rules of nomenclature (see Art. 17 ter of the „Propositions", 

 p, 3 and 23). It aims at the same object as the principle established by 

 the staff of the Royal Bot. Gard. and Mus. Berlin (Notizbl. Bot. Gart. 

 Berlin I. (1897) 245), which invalidates all the generic names that have 

 not been used for fifty years. It must be explicitly stated that, for the 

 above mentioned staff as well as for the Belgian and Swiss botanists, from 

 whom emanated the „Propositions de changemeuts", the starting-point for 

 nomenclature is the year 1753; in conformity with this, all names ante 

 dating 1753 shall not be taken into cousideration ; they are therefore ex- 

 cluded from the list of „nomina rejicienda". 



*) Propositions de changements aux Lois de la nomenclature botanique de 

 1867, dont l'adoption est recommandee au Congres international de nomenclature 

 botanique projete a Vienne en 1905, par un groupe de botanistes beiges et suisses. 

 Geneve, Bäle et Lyon. Georg et Co. 15. Janvier 1904. 



