162 



SCIENCE. 



[N. S. Vol. VII. No. 162. 



class by itself coordinate with tlie Coniferse 

 as a whole. Again, Engler's great division 

 of Embryophyta Siphonogama is seen to 

 be unfortunately named, precisely as was 

 pointed out by the writer* as long ago as 

 1892, for apparently Salviuia has the same 

 right to be described as siphonogamous that 

 Zamia has, and the real difference between 

 seed plants and archegoniates lower than 

 the Cycads appears to be one that lies rather 

 within the sphere of ecology than in that of 

 morphology ; the seed coming into existence, 

 perhaps, in more than one phylum through 

 symbiotic relationships established between 

 sporophytic and gametophytic plants of a 

 species. In brief, the group of Spermato- 

 phyta, while ecologically, is not morpholog- 

 ically, homogeneous. 



Van Tieghem,f whose interesting inno- 

 vations in the taxonomic arrangement of 

 higher plants seem to have attracted less 

 attention than their various merits deserve, 

 founds a new type of what he terms basig- 

 amous fecundation (iasif/aniie), upon the in- 

 vestigations by Webber of Zamia. A useful 

 criticism of Van Tieghem's general notions 

 regarding flowering plant taxonomy, as set 

 forth in various papers since 1894, J § || 

 will be found in the work of Eng- 

 ler previously cited. It is interesting 

 to note how the new light has been wel- 

 comed in both these taxonomic systems — 

 Engler's, representing, upon the whole, the 

 most modern development of conservative 



*MaoMillan, C. Metaspermce of the Minn. Vail. 

 25. 1892. 



t Van Tieghem, Ph. Sur une nonvelle sorte de 

 Basigamie. Journ. de Bot. 11 : 323-336. 16 Oct. 

 1897. 



J Van Tiegliera, Ph. Acrogamie et Basigamie. 

 Jour, de Bot. 9:465-469. 16 D. 1895. 



? Van Tieghem, Ph. Sur les Phanorogames sans 

 grains, etc. Compies Bend. 124 : 590-595. 22 Mr. 

 1897. 



II Van Tieghem, Ph. Classification nouvelle des 

 PhantSrogames. Compies Brnid. 124 : 919-926. 3 My. 

 1897. 



and slowly developed ideas, especially those 

 of Eichler, and Van Tieghem's, represent- 

 ing, in a radical and novel manner, the in- 

 fluence of recent cytologic work on the em- 

 bryo-sac and upon ovular development. 



The importance of these discoveries upon 

 spermatogenesis in particular have, how- 

 ever, much more than a formally taxo- 

 nomic interest, for thej'^ open up in an in- 

 spiring way a number of cytological and 

 morphological problems. They cast new 

 light upon the vexed question of the se- 

 quences among Pfceridophytes and make 

 more certain the general acceptance of Bow- 

 er's doctrines regarding the basal position 

 of the LycopodiaccEe rather than of the 

 older view of Prantl, reaffirmed by Goebel, 

 that Il3'menophyllum-like ancestors con- 

 nected the fernworts with the mossworts, or 

 the view of Campbell, who sought in Ophio- 

 glossum the primitive type. For in the 

 spermatogenesis of Zamia may be seen a 

 recapitulation of spermatozoid improve- 

 ment, and one learns how the biciliate form. 

 found in club mosses might, by the gradu- 

 ally increasing elongation of Webber's 

 hlepharoplast, or cilium-producing organ, be 

 converted into the multiciliate form found 

 in eusporangiate ferns and continued among 

 higher ferns, in Cycads and in the Gingko- 

 acete. Indubitably, then, the new investi- 

 gations strengthen greatly the position that 

 the biciliate- spermatozoid forming Lycopo- 

 dinse are, as a class, lower than the Filicinse 

 with their multiciliate spermatozoids. Pre- 

 cisely the same result has been reached by 

 investigations on the sporophytic side, no- 

 tably by Bower in the paper cited and in 

 others. * f 



Eegardingthephylogenyof Pteridophytes 



* Bower, F. O. Studies in the Morphology of 

 Spore-producing Memhers. Equisetineje and Lyco- 

 podinece. Phil. Trans. Eoy. Soo. Loud. 185 B. 473- 

 572. 1894. 



t Bower, F. O. Studies in the Morphology of 

 Spore-producing Memhers. II. Ophioglossacese. Lon- 

 don. 1896. 



