Febeuary 4, 1898.] 



SCIENGE. 



161 



two parents in all cases — or is there such a 

 thing as sexual or racial prepotency ? Do 

 sports show a prepotency in breeding ? 

 What are the limits of inheritance — to 

 what extent and to what degree are modifi- 

 cations of the soma transmissible ? What 

 are the laws and limits of crossing — the ca- 

 pacity of hybridization ; the abnormal dis- 

 tribution — the patchwork intermingling — of 

 parental characters in the body of the adult 

 hybrid? Next there are the questions, 

 allied to those of crossing, respecting the 

 reciprocal effect between scion and stock in 

 grafting. In how far is there such an ef- 

 fect and what is its cause? How about 

 the phenomena of telegony in animals and 

 of xeny in plants ? Finally, there are the 

 momentous questions concerning the rela- 

 tive importance of selection, of sporting 

 with segregation of the aberrant individ- 

 uals, of crossing and hybridization, and of 

 self-adaptation in the origin of species. 



Now, these problems are comparatively 

 untouched. Yet they are recognized as 

 immensely important. The reason why they 

 have not been worked upon is largely be- 

 cause they don't lend themselves to investi- 

 gation in the laboratory. For the success- 

 ful study of these problems one needs, in- 

 deed, not an ordinary laboratory, but a 

 farm or an extensive zoological reserve with 

 hothouses, breeding ponds, insectaries and 

 vivaria of various sorts. With such means 

 at his disposal a naturalist might hope, dur- 

 ing a long series of years, to answer many 

 of these fundamental phylogenetic ques- 

 tions. 



COBBENI PBOBLEJIS IN PLANT MOB- 



PSOLOGY. 



RELATIONSHIP BETWEEN PTERIDOPHYTBS AND 



GYMN0SPEE3IS. 



The year 1897 will always remain a 

 memorable one in the annals of plant mor- 

 phology on account of the illuminating dis- 



coveries made by Ikeno * and Hirase f of 

 spermatozoids in Cycas and Gingko, by 

 Webber % of spermatozoids in Zamia, by 

 Belajeff § || and Webber «[[ Sm ** of im- 

 portant new facts in spermatogenesis, and 

 by Bowerff of new evidence bearing upon 

 the homologies of spore-producing mem- 

 bers. 



These investigations, with others some- 

 what less notable, have already resulted in 

 some important modifications of taxouomic 

 sequence. EnglerJ| divides the subdivision 

 Gymnosperm^e into two series^ — (a) those 

 with functional spermatozoids, including 

 here the Cycadaceas, Gingkoacete and fos- 

 sil Bennettitacese and Cordaitacea?, each 

 order having also the rank of a class, and 

 (6) those with reduced spermatozoids {Sper- 

 makerne), including the classes Coniferse 

 and Gnetales. Thus the aberrant genus 

 Gingko has been removed from the order 

 Taxacete of the Coniferse and made the 

 type of a new order, which constitutes a 



* Ikeno, S. Vorlaiifige Mittheilungen iiber die 

 Spermatozoiden bei Cyoas revoluta. Bot. Centmlb. 

 69:1-3. Ja. 1897. 



t Hirase, S. Uuteisuchungen iiber das Verhalten 

 des Pollens von Gingko biloba. Bot. Centralh. 69:33-35. 

 Ja. 1897. 



% Webber, H. J. Peculiar Structures occurring in 

 the Pollen tube of Zamia. Bot. Gaz. 23: 458. note. 

 Je. 1897. 



§ Belajeff, W. Ueber den Nebenkern in Spermato- 

 genen Zellen und die Spermatogenese bei den Faru- 

 kraiiten. Bcr. Deutsch. Bot. Gesellsch. 15: 337-339. 

 27 Jl. 1897. 



II Belajeff, W. Ueber die Spermatogenese bei den 

 Scbachtelhalmen. Ber. Deutsch. Bot. Gesellsch. 15:339- 

 342. 27 Jl. 1897. 



^ Webber, H. J. The Development of the Anther- 

 ozoids of Zamia. Bot. Gaz. 24:16-22. 31 Jl. 1897. 



•:<-* Webber, H. J. Notes on the Fecundation of 

 Zamia and the Pollen tube apparatus of Gingko. 

 Bot. Gaz. 21:225-235. 30. O. 1897. (See also Web- 

 ber i.) 



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

 Spore-producing members. The Marattiace^e. Lond. 

 1897. 



tJEngler, A. Nachtrag zu Teilll.-lV. Pflanzen- 

 ham. 341. 1897. 



