' N O 



P 



R S T 



Fig. 135. — Diagrams illustrating different accounts of reduction in the flowering plants. 



A-D. Vegetative mitoses (heterotypical form) in Picea. [BelaJEFF.] 



E-I. Illustrate Strasburger's earlier account ('95) and the later one of Guignard, of the first 

 maturation-division. E. Doubly split rod. F. Metaphase, in profile. G. The same en face, 

 showing the heterotype ring. H. 1. Opening out and breaking apart of the ring. 



J-M. Later account of Strasburger and Mottier {cf. Figs. 133, 134). J. Longitudinally split. 

 V-shaped chromosome of first division. K. Opening out of the ring. L. Prophase of second 

 division, showing longitudinally split segmented spireme. M. Initial anaphase of second division. 



A''- ^'. First division. [Belajeff.] X. Longitudinally split chromosomes, viewed in the equa- 

 torial plane. O. The same viewed in the axis of the spindle. P. Separation of the daughter- 

 chromosomes. Q. Anaphase, all the chromosomes assuming the V-form. 



R- T. Second division in Iris. [BELAJEFF.] R. Equatorial plate, limbs of X's and V's break- 

 ing apart (reducing division), 5. Slightly later stage, with daughter-chromosomes still united at 

 one end. T. Anaphase. 



270 



