264 
Alfred Gundersen. 
PLANT FAMILIES: 
A PLEA FOR AN INTERNATIONAL SEQUENCE. 
By Alfred Gundersen. 
A N almost endless variety of systems and modifications of 
systems of plant classification have been proposed. While 
the growth of knowledge demands constant revision, more urgent 
practical purposes require stability. The formation of a natural 
classification has become the task of morphology and paleobotany, 
almost entirely separate from systematic botany. The ideal system 
of the future must exhibit the course of plant evolution, but the 
establishment of this exact course is distant. Must meanwhile the 
confusion from a multiplicity of systems continue indefinitely? 
Some Recent Systems. 
The Engler-Gilg classification (1912) of the higher plant is: 
EMBRYOPHYTA ASIPHONOGAMA. 
1. Bryophyta. 
2. Pteridophyta (Filicales, Sphenophyllales, Equisetales, 
Lycopodiales, Psilotales, Isoetales, Cycadofilices). 
EMBRYOPHYTA SIPHONOGAMA. 
1. Gymnospermae (Cordaitales, Bennettitales, Cycadales, 
Ginkgoales, Coniferae, Gnetales). 
2. Angiospermae (Monocotyledoneae, Dicotyledonae). 
The apparently distinct line separating clubmosses and 
horsetails on the one hand (Lycopsida) from ferns and seed plants 
on the other (Pteropsida) was pointed out by Jeffrey in 1898. Scott 
(1909) considers the construction of the pedigree of the vegetable 
kingdom to he a pious desire, which will certainly not be realized 
in our time. To Jeffrey’s groups he adds Sphenopsida, thus: 
SPHENOPSIDA (Equisetales, Pseudoborniales, Spheno¬ 
phyllales , Psilotales). 
LYCOPSIDA (Lycopodiales). 
PTEROPSIDA (Filicales, P ter idosper nice , Gymnospermae, 
Angiospermae). 
Bessey (1914) adopts six main groups of vascular plants: 
PTERIDOPHYTA (Eusporangiatae, Leptosporangiatae). 
CALAMOPHYTA ( Sphenophyllinece , Equisetineae, Cala- 
marinece). 
LEPIDOPHYTA (Lycopodineae, Lepidodendrinece). 
CYCADOPHYTA {Pteridospermce, Cycadineae, Bennet- 
tinece, Cordaitinecc). 
STROBILOPHYTA (Pinoidea?). 
ANTHOPHYTA (Alternifoliae, Oppositifoliae). 
