1 54 
Hans Hal Her. 
The general features of my system are the following : The 
Angiospermae are a natural (monophyletic) group, and not a 
polyphyletic one, as suggested by Engler in Engler and Prantl’s 
Naliirlichen Pflanzenfamilien, Nachtrag zu II.—IV. (1897), pp. 
364—369. The Amentaceae are not to be considered as old types, 
remaining in a lower state of development, and allies or descendants 
of Gymnospermae, but, on the contrary, as the highest and most 
reduced types of one of the lines of Dicotyledons. They and all 
the other lines of Dicotyledons have been developed by reduction 
in flower and fruit from the Polycarpicae, the latter group being 
derived immediately from Bennettitnceae or other extinct Cycadales. 
In the same manner the Liliijlorae and all the other syncarpous 
Monocotyledons have been derived by union of the carpels, by 
reduction in the number of parts, by epigynous insertion of the 
perianth, and by other changes in the structure of flower and fruit 
from the polycarpous Monocotyledons (Helobiae), which latter group 
originated immediately from the polycarpous Dicotyledons ( Poly¬ 
carpicae and Ramiles). In the Dicotyledons the Apetalae and 
Sympetalae are unnatural groups of polyphyletic origin. 
Agreeing in some points with mine, and likewise phylogenetic, is 
the system which Professor C. E. Bessey, of the Nebraska 
University, published eight years ago in the Botanical Gazette, 
Vol. XXIV. 
I do not claim for my system the position of an infallible 
gospel or of a “ Nolimetangere,” the latter very significant 
expression being used by Professor Karsten on p. 443 of the 
seventh edition of the Bonn Text-Book of Botany (1905). On the 
contrary, I freely confess that my system gives only an approximate 
idea of the lines of descent and of the mutual relations of the 
Flowering Plants; it is only one step in the further progress of 
phylogenetic botany. But I am sure that this step is not a wrong 
and useless one, and that it will lead to a broader knowledge of the 
natural affinities of Flowering Plants. 
The following is a chronological enumeration of the publications 
in which I have worked out my system. 
1. Versuch einer naturlichen Gliederung der Convolvulaceen 
auf anatomischer und morphologischer Grundlage. Engler’s 
Botanische Jahrbiicher, XVI., 4—5 (1893), p. 486. 
2. Betrachtungen fiber die Verwandtschaftsbeziehungen der 
Ampelideen und anderer Pflanzenfamilien. Natuurkundig Tijdschrift 
voor Nederlandsch Indie , LVI., 3 (1893), p. 486, 
