1912] PACE— PARNASSIA ' 325 



20. Shreve, F., The development and anatomy of Sarracenia purpurea. 



Bot. Gaz. 42:107-126. ^/5. j-5. 1906. 

 31. Strasburger, E., Zu Santalum und Daphne. Ber. Deutsch. Bot. Gesells. 



3:105-113. />/. p. 1885. 



22 « , Die Angiospermen und die Gymnospermen. Jena. 1879. 



2 3- — , Chromosomenzahl. Flora 100:389-446. pi. 6. 1910. 



24. Tischler, G., tjber Embryosack-Obliteration bei Bastardpflanzen. Beih. 

 Bot. Centralbl. 2:408-420. pi. 5. 1903. 



25. Webb, J. E., A morphological study of the flower and embryo of {Spiraea) 

 (Astilbe). Bot. Gaz. 33:451-460. figs. 28. 1902. 



26. Von Wettstein, R. R., Handbuch der systematischen Botanik. 



EXPLANATION OF PLATES XIV-XVII 



All figures except the diagram in fig. 70 were drawn with the aid of the 



camera lucida; Spencer ocular no. 4 and 4 mm. objective were used for figs. 5, 



3°> 45> 46, 47, 48, 67, 68, 77, 79, 80, and 92; ocular no. 4 and 16 mm. objective 



were used for fig. 69; all others were drawn with ocular no. 4, 1. 5 mm. (oil) 

 objective. 



The abbreviations used are as follows: e, egg; m, megaspore; &, male 

 nucleus; p, pollen tube; s, synergid; /, tube nucleus. 



Parnassia palustris 



Fig. i. — Young ovule with three large hypodermal cells; two shown in the 

 drawing; the third is just back of these two. 



Fig. 2. — A somewhat older ovule with four large cells in a row, evidently 

 derived from a single hypodermal cell by two successive divisions. 



Fig. 3. — A different arrangement of the large group of cells, one cell in 

 mitosis, showing 20 chromosomes; from the same ovary as fig. 5. 



Fig. 4. — Sporogenous cell differentiated as 

 inner integument is beginning to develop. 



Fig. 5. — Synapsis and beginning of outer integument. 



Fig. 6. — Two sporogenous cells; the larger one already in synapsis. 



Fig. 7. — Two sporogenous cells of approximately the same size; the two 

 cells were in the same section, one lying above the other; the larger cell has the 

 nucleus in synapsis, the other one in an earlier stage. 



Fig. 8. — After recovering from synapsis; spirem still very long. 



Fig. 9. — Ten short chromosomes; the double character can be clearly seen 

 in several. 



Fig. 10. — The two daughter cells with chromosomes formed for the second 

 division. 



Fig. 11. — The micropylar daughter cell in same stage as fig. 10; the 

 chalazal daughter cell has nucleus with spindle. 



Fig. 12.— Both daughter cells in the telophase stage; in the micropylar 

 cell one chromosome failed to reach the pole and so is omitted from the mega- 

 spore nucleus. 



shown 



