270 Alfred Gundersen. 
Marattiaceae 
Marat 9 
Araucariaceae 
Arauc 22 
Ophioglossaceae 
Ophio 7 
Pinaceae 
Pinac 23 
Taxodiaceae. 
Taxod 24? 
Osmundaceae 
Osmun 8 
Cupressaceas 
Cnpr 25 
Gleicheniaceae 
Gieich 9 
Ephedraceae 
Epned 26 
Matoniaceae 
Maton 10 
Welwitschiaceae 
Welw 27 
Hymenophyllaceae 
Hymen 11 
Gnetaceae 
Gnet 28 
Schizaeaceae 
Schiz 12 
Ceratopteridaceae 
Cerat 29 
DICOTYLEDONS 29— 
Cyatheaceae 
Cyath 14 
Polypodiaceae 
MONOCOTYLEDONS. 
Seeking a maximum of stability it is not desirable to assign 
numbers to exclusively fossil groups. For the same reason groups 
such as ferns or monocotyledons are not numbered separately; the 
position or delimitation of such groups may be different in the 
future. But with a single series as of vascular plants, possibly later 
extended to all plants, the numbers would be essentially symbols ; 
periodic changes due to improved classifications would require 
practically no new names, only a reassignment of numbers. In 
the case of a few very large families, such as the Compositae, it 
might be preferable that the numbers should refer to tribes. The 
thought is here of the co-ordination of information rather than of 
the arrangement of collections. 
The angiosperms in the Pflanzenfamilien are arranged according 
to a rigid system of floral morphology. Among questions which 
would need to be considered in a possible rearrangement are : 
(a) . Whether woody plants should generally precede her¬ 
baceous ones within a given relationship ; 
(b) . Whether at least apetalous herbaceous plants should 
follow related polypetalous ones; 
( c ) . Whether Piperales should be removed from its position 
between Casuarinacece and Salicacece to a later position perhaps 
near Polygonacecz; 
(d) . Whether Proteacece should be nearer the earliest 
angiosperms; 
(i e ). Whether Aizoacece and Cactacece are related ; 
(/). Whether Caryophyllacece , Linacece and Gentianacece are 
related; 
(g) . Whether Cornacece should be near Caprifoliacece ; 
(h) . Whether Cucurbitacece should be near Passifloracece ; 
