26 METASPERMAE OF THE MINNESOTA VALLEY. 
between such a condition as that of Azolla caroliniana among 
the Zoidiogama and Taxus baccata among the Siphonogama. Not 
only does it seem that the presence of pollen-tubes or of 
spermatozoids is a matter of secondary taxonomic importance, 
but it is perhaps hardly advisable to use a purely gametophytic 
character to limit off a group like the Embryophyta siphonogama 
which, to-day at least, comprises species described almost 
solely from sporophytic characters (a). While accepting the 
general arrangement of families as given in Engler’s great 
work we cannot then, accept unquestioningly his broad group- 
ings of the vegetable kingdom. However, it is possible that 
longer study will bring the classification of Engler into a more 
acceptable light. For the present it seems preferable to the 
writer to insist upon the basal importance of the sporophytic 
segmentations of plant ova and the subsidiary importance of 
spermatogametic and spermatogonial morphology. 
There are a number of considerations in this general taxo- 
nomic summary which demand more complete examinaticn, but 
enough has been said, it is hoped, to limit intelligibly though, 
to a certain extent, technically, the group of plants which are 
studied in the following pages. The Metaspermae are believed 
to be a natural group of plants properly co-ordinate with the 
Archegoniatae and Thallophyta(in the narrowersense). Reasons 
for breaking up the old Phanerogamiae, Anthophyta or Sperm- 
aphyta of the authors have been brought forward, and it is 
believed that many could be added. Certainly the wide differ- 
ence between the seeds of Metaspermae and Archispermae 
stands squarely in the way of grouping them in the same grand 
division of the vegetable kingdom. Their separation has been 
proposed before (39), but not in exactly these terms. The 
sharp division of Sporophyta and Gamophyta has been proposed 
elsewhere by the writer (393), with, however, a somewhat 
different limitation of the terms. Attention is directed partic- 
ularly, in the preceding pages, to the characterisations of 
Metaspermae and Archispermae, which have the merit at least 
of being restatements of facts which are generally to be looked 
for in scattered corners of morphological treatises. These 
characterisations are different in essential particulars from 
those usually given, which are based for the most part upon 
(a). See division into Protosporophyta, Eusporophyta and Metasporophyta in (39%) 
cited below. 
(39). Goebel: Outlines of Classification and Special Morphology. Eng. Tran., Introd. 
(1887). 
(39%). MacMillan: Suggestions on the Classification of the Metaphyta. Bot. Gaz.(1992). 
