1858 , Journal of Applied Microscopy 



CURRENT BOTANICAL LITERATURE. 



CHARLES J. CHAMBERLAIN, University of Chicago. 



Books for Review and Separates of Papers on Botanical Subjects sliould be Sent to Charles J. 

 Chamberlain, University of Chicago, Chicago, ill. 



Karsten, Q. Ueberdie Entwickelungderweib- The forms studied wtxe Jug/ans rcgia, 

 lichen Bluthen bei einigen Juglandaceen. y coniiformis, J. nigra, Pterocarya frax- 

 Flora, 90: 316-333, pis. 12, 1902. r ■ r^ ^^ 



Diifoiia, Larva ainara and C. tonientosa. 



\x\ Juglans cordiformis at the time of fertilization and even later, the union of 

 the carpels is delayed, thus leaving the ovules exposed so that the condition is 

 hardly different from that in Gymnosperms with orthotropous ovules, e. g., in 

 Gneti/m. 



There is an extensive sporogenous tissue in the nucellus, but any further 

 development is usually restricted to a single cell in the median line. 



The megaspore mother cell may develop directly into the embryo-sac or may 

 give rise to a row of three or four potential megaspores, of which the two upper 

 ones never develop, but the two lower seem to have equal chances. Many cases 

 were found in which there were two embryo-sacs in the median line, one above 

 the other, sometimes touching each other at the ends, but often separated by 

 several layers of sterile tissue. A case is figured in which the sac next the chal- 

 aza has been fertilized. The egg and synergids oi/i/g/aiis nigra cannot be dis- 

 tinguished definitely before fertilization. The union of the polar nuclei is delayed 

 for a long time and perhaps does not occur at all. Double fertilization was 

 observed, and the writer believes that, in all cases, the union of the male nucleus 

 with the polar nucleus takes place earlier than the fertilization of the egg. 



Although the occasional occurrence of hermaphrodite flowers may indicate a 

 reduced rather than a primitive condition, the Juglandaceae are to be regarded 

 as one of the lowest families of the Angiosperms. Prof. Karsten would derive 

 the Angiosperms from the Gymnosperms, making Gncfiim the point of contact. 

 His argument, based almost entirely upon embryological characters, is well 

 summed up in his diagrammatic comparison of the Gnetum and Angiosperm 

 embryo-sacs. 



Gnetum embryo-sac = Angiosperm embryo-sac 



Prothallium in lower part = Antipodals 



Egg cells = Egg cell -^ synergids 



Endosperm nuclei ^ Polar nuclei 



, , ^ ^ fThe stimulus to development of the 



The stimulus to development of ) ^^,^ . fertilization of the egg and 



embryo and endosperm by the fer- v = ^ development of ihe endosperm by " veg- 

 tilization of at least two egg cells. ) [^gt^tive fertilization." 



c. J. c. 



c^ . cj 1- • T) 1 A^ This paper emphasizes the fact that 



Strasburger, Ed. Einige Bemerkungen zu der ^ '"-^ i^c^^v, ^^ 



PoUenbildung bei Asclepias. Bar. d. deutsch. the embryo-sac mother cell and the 

 bot.Gesell. 19: 450-461, pi. 24, 1901. p^^gj^ mother cell are homologous 



structures. There is the least deviation from the primitive condition when an 



