222 BOTANICAL GAZETTE [SEPTEMBER 
retained. Ephedra has also retained it in a modified form, and 
this definitely associates Gnetales with the Coniferales rather than 
the cycads. 
14. The other evolutionary lines suggested in the discussion 
likewise assign a primitive position to Pinus, so that this ancient 
type seems to be genetic to several conifer lines. 
15. The body regions of the later embryo, so far as they have 
been determined, appear in the following order: plerome tip of 
root, periblem and root cap, stem tip, and cotyledons. 
16. There is a distinct tendency in P. Banksiana toward a 
reduction in the number of cotyledons, attested by the fact that 
2 primordia have been found to form 1 broad cotyledon. This 
suggests that the dicotyledonous condition has been derived from 
the polycotyledonous condition through cotyledonary fusions. 
17. Cotyledonary tubes are the result of past cotyledonary 
fusions, and are found in embryos between the primitive polycoty- 
ledons and dicotyledons. : 
18. The zygomorphic feature of a monocotyledonous embryo 1s 
foreshadowed in the embryo of Pinus. 
This investigation was begun in the summer of 1914 at the 
suggestion of Professor Joun M. Coutrer, and continued through 
the summers of 1915 and 1916. Acknowledgments are due to 
Professor CHARLES J. CHAMBERLAIN, whose suggestions from time 
to time were very valuable, and likewise to Professor W. J. G 
Lanp and other members of the botanical staff of the University 
of Chicago, where the major portion of this work was done. The 
writer is also indebted to Professor Joun H. SCHAFFNER, who 
kindly loaned the slide of fig. 36. 
West Texas State NorMAL COLLEGE 
Canyon, TEXAS 
LITERATURE CITED 
1. ARNOLDI, W., Beitriige zur Morphologie einiger Gymnospermen. V. 
Weitere Untersuchungen der Embryogenie : an se der Sequoiaceen. 
Bull. Soc. Imp. Nat. Moscow, pp. 28. pls. 
2. Brown, RoBert, in Capt. Philip P. King’s éaarvey of the Western and 
Intertropical Coasts of Australia.” London. 1826, Appendix B, p. 5573 
also Ann. Sci. Nat, I. 8:211. 1826. 
