No. 12.— Botanical Gazette —Dec, 1891. 



On the relationships of the Archegoniata. l 



DOUGLAS HOUGHTON CAMPBELL. 



Under the name of Archegoniata are usually included the 

 bryophytes and pteridophytes, but we may also include with 

 them the gymnosperms, as all three groups agree in the pres- 

 ence of an unmistakable archegonium, which while differing in 

 some details has such similarity of structure as to point to an 

 almost certain, although remote, common origin for all three 



groups. 



This homology was first shown by Hofmeister 2 in his re- 

 markable series of investigations upon the higher cryptogams 

 and gymnosperms, and has since been the subject of num- 

 erous investigations, so that a great mass of material has 



accumulated. 



Numerous attempts have, of course, been made to trace out 

 the inter-relationships of these groups; but recently a good 

 many new facts have been discovered which may throw a 

 somewhat different light upon these, and it is the intention 

 here to call attention to these, and attempt to point out what 

 their bearing is upon the point in question. In trying to do 

 this, the data assumed are mainly derived from the results of 

 a developmental study of the different forms, coupled with 

 such evidence as the palaeontological record has to show. 

 Unfortunately the latter is too fragmentary, as regards the 

 lower forms and the more delicate parts of the higher ones, 

 to be of very much service in the study of these points; still 

 very valuable material has been brought to light, and prob- 

 ably much more will be discovered if a systematic search is 



made. 



It is generally admitted that we are to look for the ances- 

 tors of the higher plants among the fresh water green Alga. 

 On account of the structure of the sexual organs, as well as 

 the occurrence of a sort of protonema, the Characea; have 

 sometimes been regarded as the nearest approach among ex- 

 isting Algae to the mosses; but if this is so, the ancestral forms 

 must have been of a much less specialized ch aracter than even 



1 Read before Section F, A. A. A. S.. Washington Meeting, August, 1891. 



2 The higher Cryptogamia. 



