26 METASPERMAE OF THE MINNESOTA VALLEY. 



between such a condition as that of Azolla cat^oliniana among 

 the Zoidiogama and Taxus baccata among the SipJionogama. 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 Emhryophyta 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 examination, 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 Thallophy ta(in the narrower sense) . Reasons 

 for breaking up the oldPhanerogamiae,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 Gamophy ta has been proposed 

 elsewhere by the writer (39^), with, however, a somewhat 

 different limitation of the terms. Attention is directed partic- 

 ularly, in the preceding ])ages, 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). Soe division Into Protosporophyta. Euspoi'opliyta and Metasporopliyta In (39!4) 

 cited below. 



(39). Goebel: Outlines of Clnssiflcation and Special Morphology. Eng. Tran.. Introd. 

 (1887). 



(39V4). MacMlllan: Suaaestions ontheClasniflcoiionof the Metaiihuta. Bol. Ga7,.(1892). 



